how to make the player stop at other objects (collision?)

How do I...?
1

my player n bullets keeps on going through other object so how to make the player stop when walking into other objects?

2

Simply check the collision between player and other objects by using “All Objects/Collision/Collision” or “Sprite/Collision/Collision (pixel perfect)” condition and to stop player when it colliding just use “All Objects/Position/Separate two objects” action.