rar text files


I am not using Blender that often but I’m getting on quite well for simple, still architectural renderings (Blender for Mac).
For some interiors I am downloading some objects like furniture and light fittings etc. from free sources which has worked fine so far. However, I have now come across more and more files which, once downloaded, open in a window as a text/script (often rar). I tried to copy these into UnRarX but it won’t recognise these files.

How do I make these files usable and get the models to work?

Many thanks in advance