Use the PickUp script to pick up ammo/health kits and weapons. This script has 2 types of pickups: "Raycast" and "Collider".

Collider mode

When the character enters an area, he picks up an object.

Raycast mode

When the player is in the area and the crosshair is pointed at an object, click on the [Pickup] button to pick it up (you can edit the button in the Input Manager [Edit -> Project Settings -> USK Input ]).