Here’s how Code-tags
All your code is doing is permanently (per-frame) setting the velocity to (0, 10) i.e. up. That’s all it does.
You should follow one of the many, many tutorials on the subject of 2D physics movement. Then you’ll have a better idea on how to control it correctly and should be less frustrating for you. 
Search “unity 2d physics movement tutorial”.
Hope this helps.