The video linked below can only be used when your new character mesh uses the UE4 mannequin skeleton. Here is an example of a character skeleton using the UE4 Mannequin skeleton (Image). This video is only for Unreal Engine 5.
The video linked below should be used for all character meshes that do not use the UE4 mannequin skeleton, this includes the UE5 mannequin skeleton. This video is only for Unreal Engine 5.
If you are using Unreal Engine 4 you can follow the video linked below for all character meshes. This video is only for Unreal Engine 4.