3D Printing STL from FCSTD Format

Newbie question of the day… How do I produce STL files from the FCSTD ones from GitLab? I have FreeCad and have tried exporting them but the resultant STL files look ‘significantly’ different. i.e., no detail/solid or look very different.
This is my first venture into 3D printing as you can probably tell, so any help will be graciously accepted :slightly_smiling_face:

** edit:
Just found these on git hub (still be good to know why mine look different…)