Just one quick question.
Is there a way to have a working gun or just when you click with mouse it shoots in that direction?
First, RM default does not have a mouse function.
Second, RM default battles are outside the map and have no ranged functions
For both problems there are scripts - mouse scripts to enable mouse control of the game, and ABS-Scripts to allow for battles on the map that use ranged attacks.
However, both types of scripts require some thought and configuration, they should only be used after you have some experience with making games in RPG makern. Especially ABS-Scripts usually require a lot of configuration, and most mouse-scripts either work only with default menus or require modifications if you changed the menues by scripts.