How can I add Props of Addon in Hammer Editor (Gmod Map)?

Hello , anyone can help me to add a props of an addon? I didn’t find tuto about this. I tested a few of things but the only result I have is a model of the props I want but he is untextured in the Hammer Editor (Black and Pink square) and when I test the map on Gmod , the model don’t appear. Sorry for my english,I am french. I hope you understood what is my problem.Thank you for reading this message :).

the Black and Pink squares that appear in hammer are to show that you don’t have the materials for the prop in the correct folder, that is why they don’t show in game, check you have the materials in the right folders and you should be ok

Ok but where is the good folder ?

when you look at the addon files are they in model and materials if they are just place them in the garrysmod folder and they will merge with the gmod content

Thank you a lot , I found with your help the right folder.