how to control facial rig and animate it
Hey Brainias1
Firstly, welcome to the forums! 
Here are some resources you should find useful.
Animating with the Control Rig Sample Project | Inside Unreal
Animating with Control Rig in 4.26 | Inside Unreal
Using Control Rig in Unreal Engine
Animating MetaHumans with Control Rig in UE | Unreal Engine
Using the MetaHuman Facial Rig in UE | Unreal Engine
And lastly, the Control Rig Documentation
I hope they help! 
see I know how to use them and how to animate with metahuman facial rig just dont know how to control it but cant animate it with the sequencer once edited and adding a new key at that time it remains same at all places and dont change with time