Nothing dude... Are you stupid it something?
Go to garrysmod.org and download various addons. These after download are usually extracted to the [Steam Install Folder]/steamapps/[Steam User Name]/garrysmod/garrysmod/addons folder. But these addons have installation instructions most of the time.
You do not have the correct addons needed for those props. That's why there is an error, get used to the names of addons, then download and install them from garrysmod.org
The easiest way to get addons and install them are with one of the two major addon clients, The Curse Client (requires a curse account) and WOWInterface's Minion. To manually install an addon, you need to download it to your computer, unzip it if it is zipped and then move it to your %wowfolder/interface/addons/ directory.
Depends on what kind of things you want on your game for addons, and Maps get them off of GarrysMod.org Heres how you install them Program Files > Steam > SteamApps > YourUserName > GarrysMod > GarrysMod > Addons Program Files > Steam > SteamApps > YourUserName > GarrysMod > GarrysMod > Maps
You can download a client from Curse (see related links below) that makes it sooo much easier to download add-ons too. WoWInterface also has a client that lets you download and install addons from their site. Both sites are safe.
download the addon. Should be on a zip file. Simply extract the file. place the folder with all the files in your >world of warcraft>interface>addons folder.
You should download the curse client and download the addons via that, on my computer the addons automatically go to the WoW addons folder located in the interface section of the WoW folder.
Download a wow addon manager like wowmatrix. Google Wowmatrix --- Inside your World of Warcraft game folder you will find a folder called "Interface". Inside is a folder called "Addons". Addons provided on abovementioned websites usually come zipped, with the files in a folder with the addon's name. Simply copy this folder entirely into the "Addons" folder. Make sure to quit WoW and restart it. At your character selection screen, at the bottom right, is a button "Addons". Click it to see a list of addons you are using. Make sure all addons you want to use have a tick in the box, and that the box "Load out of Date Addons" is ticked, in case you installed an older addon. Log into your character, and the addon should now be active.
It depends on what you want to download, first get what you want to download off of garrysmod.org Maps go in the steam/steamapps/(username)/garrysmod/garrysmod/maps file addons go in the steam/steamapps/(username)/garrysmod/garrysmod/addons file
you have to get the program wowMatrix from there you can get all the addons you need.
Go to Firefox.com, click Addons, and in the sidebar click Plugins.
can be because some addons on your browser, just check which on is or are causing problem of not showing download bar. Alternatively there are free download manager just check one of them.