And, when I try playing my own tracks, it brings me back to the track editor screen :( .

That means you haven't built the track properly. It will take you back to the editor screen with the cursor on the spot where something is broken. Every track must have a beginning and an end which are mutually connected by a road. I also think you can't have road segments outside of the track or that end nowhere. I'm not sure anymore, but check that you have done it properly