Make sure you have an AWS account with administrator rights and are logged into that account.

Visit https://console.aws.amazon.com/iam/home?#security_credential and extend the 'Access Keys' element.

Press 'Create New Access Key' to get your Access Key ID and Secret Access Key

Go to https://cloud.google.com/storage/.

Choose 'Try it free' (you may have to log in) and complete the registration for Google Cloud Storage.

Use this link to create a new Google Console project: https://console.developers.google.com/iam-admin/projects.

Click the 'Create Project' button and give your project a name.

Type 'storage' in the search bar, select 'Google Cloud Storage' and then select 'enable'.

Click on 'Credentials' in the navigation bar on the left.

Select 'Create credentials' -> 'Service account key'.

Click on 'Select...', choose 'New service account', fill out the empty fields and click 'Create'.

Download the generated JSON file and use the content of the 'client_email', 'private_key' and 'project_id' fields.

For the private key, use the whole string including '-----BEGIN PRIVATE KEY-----' and '-----END PRIVATE KEY----- '

Make sure you have a Microsoft Azure account with administrator rights and are logged in to that account.

In the dashboard overview, go to 'Storage Accounts'.

Create a new one by clicking 'Add' and fill in the required details according to your preferences.

The name of the storage account is your 'account name'.

Click on the account and go to 'Settings/Access key' where you can find your 'access key'.

Use this link to create a new account: http://box.com/developer_signup.

Use this link to create a new app, when you already have an account (you may have to log in first): https://app.box.com/developers/services/edit/.

Give your app a name and click the 'Create Application' button.

On the page you are redirected to, you can edit the settings of the app and you'll also find your App Key (Client ID) and App Secret (Client Secret).

Set the Redirect URI to an endpoint on your server ready to receive redirects or localhost for testing with a local server.

Use this link to create a new app (you may have to log in first): https://www.dropbox.com/developers/apps/create.

Select 'Dropbox API', then select 'Full Dropbox'.

Give your app a name and click the 'Create app' button.

On the page you are redirected to, you can edit the settings of the app and you'll also find your App Key (Client ID) and App Secret (Client Secret).

Set the Redirect URI to an endpoint on your server ready to receive redirects or localhost for testing with a local server.

Use this link to create a new project (you may have to log in first): https://console.developers.google.com/iam-admin/projects.

Click the 'Create Project' button and give your project a name.

Type 'drive' in the search bar, select the 'Google Drive API' and then select 'enable'.

Click on the 'Go to Credentials' button.

You can skip the Google helper and just click on 'client ID'.

Click on the 'Configure consent screen' button and fill in the necessary text fields.

Select 'Web Client', choose a name and set the Redirect URI to an endpoint on your server ready to receive redirects or localhost for testing with a local server.

Now you receive your Client ID and Client Secret.

Use this link to create a new app (you may have to log in first): https://apps.dev.microsoft.com/#/appList.

Click the 'Add an app' button and give your app a name.

On the page you are redirected to, you can edit the settings of the app and you'll also find your App Key (Client ID) and App Secret (Client Secret - 'Generate New Password').

Click on the 'Add Platform' button and select 'Web'.

Set the Redirect URI to an endpoint on your server ready to receive redirects or localhost for testing with a local server.

Tick 'Live SDK support' under 'Advanced Options' at the bottom of the page.

Click 'save'.

The following instructions assume that you are not familiar with Azure's Active directory configuration. If you are, however, feel free to alter any of the following steps to your liking, as long as you end up with a valid Client ID, Client Secret and the ability to set a redirect URI.

Register an Office 365 developers site if you do not already have one. You can start a free trial at https://portal.microsoftonline.com/Signup/MainSignUp.aspx.

Next, you need an Azure Active Directory tenant if you do not already have one. Make sure you are signed into your Office 365 tenant and go to the admin center.

In the same browser, open https://account.windowsazure.com/SignUp to sign up for a Microsoft Azure account.

Go to https://manage.windowsazure.com/ and navigate to 'Active Directory'.

If you have no directory listed, switch to the 'Directory' tab, click the 'New' button on the bottom left and click 'Directory/Custom Create' to create a new directory.

Click on your directory and go to the 'Applications' tab.

Click the 'Add' button at the bottom and choose 'Add an application my organization is developing'.

Choose a name, select the 'Web application and/or Web API' toggle and click continue.

A Sign-on URL is required but not relevant here, you can take e.g. 'https://<your_domain>.onmicrosoft.com' if it's not taken. The same holds for the App ID URI.

Sometimes Azure will tell you that an error occurred and that you have to try again. Just wait a bit and reload the page, your just created application should be there anyway.

Select the application and go to the 'Configure' tab.

You can customise what your users see when your application asks for access.

Make sure to switch 'Application is Multi-Tenant' to yes.

Client ID is the client identifier you need.

You will probably want to have 'User assignment required to access app' set to no.

Generate a new key in the 'keys' section, this is the client secret you also need.

'Reply URL' lists the valid redirect URIs. Set it to an endpoint on your server ready to receive redirects or localhost for testing with a local server.

Click 'add application' to add the necessary permissions for your application.

Select 'Office 365 SharePoint Online' and add the delegated permissions for 'Read and write user files' and 'Read user files'.

Make sure to save by clicking on the button at the bottom.