You need Steam Workshop Downloader
link {LINK REMOVED}https://steamworkshopdownloader.io/
A model to port which is optional
the extended spawn menu
link https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=104603291
and Garry's mod OF COURSE

this is a optional thing you can port anything you want from any where and i always use SFM to port from and if you want to upload it then you have to ask perm. from the creaters. So when you find your model you right click and you will see "Copy Page URL you click that. Make sure the model you have is one you like so you can be happy with what you have.

So this one is easy you go to this link
{LINK REMOVED}https://steamworkshopdownloader.io/ So once you copy the model URL you copy it in the search bar. then you click the download putten

So you go to your Garrys mod in your library and you right click then you click manage and then you click browse local files. then you double click the garrysmod under the bin then you go to addons then you make a new file then name the file what you want then open the recycle bin then you go to downloads then find the model you have downloaded open the file no need to extract it. so then you select the "materials" and the "models" bye holding ctrl and clicking on both then you drag the materials and the models into the new file you have made

So when your done with all of that stuff you must log into garry's mod once you do that you open the spawn menu you can use ANY map you want and once you in Gmod you extend the "legacy addons"
and you should see your file with your models in the file OK IT WORKED for me i don't know if it worked for you but now if it worked just spawn it
BOOM IT'S DONE NOW YOU CAN DO WHAT EVER YOU WANT WITH IT YAY

So are you happy if it worked and if i did not and if you don't like reading that's fine THANKS TO ROCCO THE PUPPET https://www.youtube.com/watch?v=4mfuDbO5ua8
he made a video on how to port this is how i did my first port so if this did not work you got this mate most of my friends wanted it so here it is let me know if it worked or the rocco video THANKS PEOPLE SEE YOU NEXT TIME AND IF YOU NEED HELP WITH ANYTHING ELSE ON GMOD COMMENT IT AND IF I DON'T KNOW HOW TO THEN i don't know mate