First, make sure the Live Link is broadcasting properly. We cover this in another article: Live Streaming in Unreal Engine 5 – PERCEPTION NEURON (neuronmocap.com)
Go to Window→Cinematics→Take Recorder
Click on Source→From Actor
Select the character in your scene being driven by the Live Link data
Make sure the data is streaming, and then when you are ready, click the red circle to Record
Click Stop when you are done
Playback your Recording
Takes are stored by default in the Take Browser
To access the Take Browser, go to Window→Cinematics→Take Browser
Every take creates 3 different files: a Level Sequence, an Animation Track, and an Animation Sequence
The Level Sequence functions just like any other sequence and if you click on it in the sequencer you can access the Animation Track
The Animation Track is where you can edit the keyframes if desired. You can also drag the Animation Track into other Sequences
The Animation Sequence created functions like any other Animation Sequence. In the Animation Sequence Settings, make sure Force Root Lock is turned off