It’s always hard to help someone with a topic as general as making a robot…
The first step would be to decide what you actually want to do, precisely.
How do you want your robot to move? Will it be moved with the arrow keys? Will it be autonomous with some sensor? if yes how many? what kind of sensor?
What is the environment? Just some randomly placed rectangle as obstacles? A real image where you extract obstacles from?
Once you have the idea where you want to go, start simple. For example just start with a robot that can move. Then add one simple obstacle. Then add one sensor. and so on…
Once you have done something (with code) and if you are stuck, come back and we’ll help you. But right now, there is not much we can do.