Add files to an existing asset

From the MK.IO Dashboard view, navigate to Assets from the left-hand side menu.
From the list of available assets, click on the name of the asset to which you want to add files. You are then presented with the properties of that asset.
Scroll down towards Tracks and click the Files on storage tab. This will list any file already included in the asset.
To add a new file, click the Add Files button.
Click to browse or drag the file(s) you want to upload.
Confirm the upload by clicking the Upload button. The new files will be uploaded and the existing asset will be updated.