To migrate your WordPress website from another provider to Umbler, first you need to configure your domain in your Control Panel, by following this tutorial: Adding a website to your account.

Now you need to migrate your website files: Migrating a website to Umbler.
and your database: Migrating your database to Umbler.

Now that all your files and database are hosted at Umbler we need to reconfigure your database connection string in WordPress. Access the Database tab in your Control Panel and copy the information like: Name, User, Password & Server.

With this information at hand, open up your Control Panel's File Manager and edit the following file: /public/wp-config.php

Done! Now your website is all set at Umbler, time to check if everything is alright.

In order to test, we need to define the WordPress URL to work directly inside Umbler. We will use the temporary address, used for tests :)

In order to do so, first, you will have to check what your temporary address is. Go to your Control Panel and click on the little arrow to open up the pane with the different URL's available:

Now open up your /public/wp-config.php again and add the following lines:

define('WP_HOME','http://your-temporary-address-com.umbler.net');
define('WP_SITEURL','http://your-temporary-address-com.umbler.net');

Remember that after testing your WordPress site at Umbler and after being satisfied with the outcome you need to change your DNS to work directly at Umbler and delete the last two lines added in this tutorial, so the access will happen through your main domain.