Grab any file you want by left-clicking and holding on it and simply drag it from your computer (e.g. from Files or Desktop) to the location in Web Drive where you want it and drop it.
The file will now be uploaded automatically.

Right-click where you want to upload a file in Web Drive. In the box that appears, you will have the options "Upload files" and "Upload folder".
Click on one of the options and select the file you want to upload in the window that appears.

Click New in the top right corner of your Filen Web Drive.
Click on "Upload files".
Select the file you want to upload and confirm.

Right click on the folder.
Navigate to "Color".
Hover over it and choose the color you want the folder to have.

You can simply drag and drop files around. To do this, grab each file by holding down left click over it. Drop the file where you want it by releasing the left click.
You can drop files or folders on top of other folders to store them inside.
If you hover a file over a folder for more than a second, you will automatically be taken into that folder. You can move through several subfolders with a file in the drag.

You can create a new folder at any time using the "New" button in the upper right corner of the Filen Web Drive or by right-clicking.
You can create as many subfolders as you want.