how do I make a character enter a vehicle?

I'm making a free roam game and I got the player and vehicles working how i want but I cant figre out how to make the player enter and exit a vehicle. Also this is third person so i want him to sit in the vehicle when he is inside it. I already have it so when a car is active the main camera follows that car i got that so far.

In that case you've already done the hard part, simply hide the player model and enable a dummy model of the player as a child of the car so it appears the player is in the car. If you want the player to climb in and out that simply means you need to animate it. There are countless similar questions on here already if you used the search.