How can I animate objects like the bag in the video?
I think you need to weld it to the character.
Weld it to the correct body part of the character and make sure the animation type is “action”
put the object in a rig and add a motor6d
This one is easy, one bag with the character, rigged to a bone parented to arms. A weld cant be used by itself, since the bag is not always “attached.”
Normal animation
Stage 1: move bag to arms.
Stage 2: move character, bag follows.
Stage 3: “Drop” bag by moving it away again.
Stage 4: Set transparency to 1, reset animation, turn off transparency.