I have done this before so this is how to tame.

1. Prepare

Large bear trap

Four metal dino gateways

3 cryopoded baby rexes

4 cyropoded dinos with HIGH health

a flier

2. Locate

Look around mountains only one can spawn at a time so look hard!

3. Set up

Set three dino gateways making a box with one open side put bear trap in middle

4. Lead the carchar into the trap and then place the final gateway

5. Get a baby Rex cryo sick, unclaim it, and feed it to the carchar DO NOT TRANQ THE CARCHAR

6. Get one of your high health dinos cryo sick, unclaim it and mount the carchar and eat it

7. Ride the carchar into the trap and repeat

8. If you run out of big dinos to feed run around the wild and kill wild dinos

9 Enjoy your carchar!

Thx for reading, this took a while to make, so if it was helpful you know what to do!