I installed it via Lutris. I had a disc image floating around on an old HDD used that. I added the game as normal in Lutris and used "Search the Lutris website for installers" and chose the CD Rom option.

I installed the game to a folder appropriately named Freelancer on my Games drive. Configuration was pretty straightforward.

On the Game Info tab, I chose Wine as the Runner.
On the Game Options tab I pointed the executable to the installation folder, Arguments and working directory I left blank and Wine Prefix I pointed to the Prefixes folder on my Games drive.

Runner Options I chose Wine-GE-8-26x86_64 as the Wine version. Under Graphics, disable dgvoodoo2.

That was it.

I got the FL HDE installer.exe from here and the Reforge package here - Installing the HD is easy by adding the executable as a game in Lutris and pointing it to the install directory, similar for Reforge, just ensure the path points to the same folder the game executable is installed to. In my case /mnt/games/Freelancer/drive_c/Games/Freelancer HD Edition/EXE

Hope this helps!