Hi Kiyki it seems you have two separate problems:
1) how to build the game you want
2) learn how to use the range of features available in Construct 2
I reckon you should focus on the second problem first, perhaps making some smaller simple games that contain just one or two of the features you need for your main goal.
Once you've built a little more experience you should find your goal much easier.
It might also open your eyes to some other things you could do within your main game - or beyond.