How do i make someones character move?

ok so im making a game where in the begining theres a cutscene i already have a camera so i dont need help with that but i want to make the person playing my games avatar put on a headset and be teleported to a new game how do i make the persons avatar walk

There are animation plugins which are helpful, just create a body rig which will be the players body-double. Get the appearance of the character and dress the body rig the same.

Animate the rig to do whatever you want, then transition with a black fade or a teleportation animation or something, after that just load the camera which is looking at the actual player!