Hello,
Just drag and drop the .dna files to unreal engine, after dragging it a window will popoup, select the skeleton mesh ( the one that you have already imported, not the archtype ) save, close all tabs, and everything should works fine.
Also dont forget to assign both the anim_postprocess and control rig to your imported head.
the .dna files are located under the file path to megascan library :
…\Megascans Library\Downloaded\DHI\AAAA\8k\asset_ue_source\MetaHumans\XXXX\SourceAssets
AAAA the name of the folder containing the metahuman project ( random name created by bridge )
XXXX is the Metahuman model name
Goodluck