NobalChase, I get that but my point in the above rant was that what your asking in such a generic way is a very large topic with lots of different methods of handling.
It like if Columbus prior to sailing to the Americas asked "How do you navigate?"
What you are trying to do is the FPS or MMO version of 2d game design.. as in everyone wants to do that to start with. What this means to you is there are TONS of tutorials and forum threads on how to do everything you asked due to others that have came before.
You will benefit yourself using them and learning your own style over having a dozen "How I would do it" or useless capx your never going to use posted here
That said (and rest assured it wasn't aimed at you alone.. but many, many, many Construct2 users...)
If you really want help, you can still keep it short but also to the point:
EXAMPLE:
Hi all, I am wanting to make a top-down shooter where my player shoots at enemies who are smart and hide behind cover and pop out to shoot at him.
I have already got my player moving and shooting and the enemies are destroyed when I hit them but I can't figure out how to make the use cover, or pop out.
Can anyone help me with this?