How to extend the action of an animated character

Here is the situation:

You want to create a video with a specific character. Cool.

I chose a 3D character called "Gym guy". In my video, I want to see him running in the park, but I just noticed that the "running" action is super short.

No problem. We can fix this. 

All you need to do is to click on the track > click on "Add action" > repeat as many times as you like.