Newbye question defrag on Linux

Hi,
One day I came across a youtube video of q3defrag with a map called “bug100” and I tried to install ioquake with defrag on Linux. Well, I have a “defrag” directory, I got the “bug100” map, I put it in various places but I can’t load it from the defrag mod when we launch Q3. Sorry if this question is stupid, but any help will be nice. THANKS !

PS: in my install, I can play q3 and q3arena, but when I load the defrag mod, it says that there is no map.

Wow! Thanks for your efforts and this comprehensive answer. I’ll look at all this step by step and let you know if it works (and I think your explanations will solve my problem, because I already have some defrag maps that work, so I must have forgotten something).

Cheers

Twoony