You will need to download TortoiseSVN
Once you have downloaded and installed this program
I suggest if you have never used this before to follow the instructions on the WireMod site.

You need to install the below addons otherwise you will see ERROR signs on the server.

WireMod
Username = anonsvn
Password = anonsvn
AutoLink = Adv Duplicator (You need this)
AutoLink = wire (You need this)
AutoLink = wire model pack 1 (You need this)
Notes = Download to a folder on your desktop, once completed open the folder and move Adv Duplicator, wire & wire model pack 1 to your garrysmod addons folder. (you can delete the folder they where previously in)

Unofficial Wire-Extras
Username =
Password =
AutoLink = Tortoise AutoLink
Notes = Create a folder in your garrysmod addons folder called UnoWire then use the checkout.

PHX3
Username =
Password =
AutoLink = Tortoise AutoLink
Notes = Create a folder in your garrysmod addons folder called PHX3 then use the checkout.

The below addons have been disabled. There is no need to install these.

StarGate
Username = anonsvn (may not be needed)
Password = anonsvn (may not be needed)
AutoLink = Tortoise AutoLink
Notes = Download to a folder on your desktop, once completed go to /trunk/addons (inside the folder you downloaded this to) and move stargate, catdaemon_stargate, stargate_resources & gmdm_resources to your garrysmod addons folder. (you can delete the folder they where previously in)

StarGate Overloader
Username =
Password =
AutoLink = Tortoise AutoLink
Notes = Create a folder in your garrysmod addons folder called SGO then use the checkout.