Extract your HUD folders, they should come in separate folders.
If you use FLMM -
Copy and paste those folders to (x:\Freelancer Mod Manager\Mods) where x is the drive you installed FLMM to.
Run FLMM and activate the HUD mods alongside Discovery mod.
If you don't use FLMM -
Make a backup of your current HUD files (x:\Program Files\Microsoft Games\Freelancer\DATA\INTERFACE) and (x:\Program Files\Microsoft Games\Freelancer\DATA\SCREENS).
Copy the files of your desired HUD from the extracted folders into your Freelancer directory while overwriting your current files.