Do not use the curse client, there is talk of it having back doors and people loosing accounts, better safe then sorry.
To install manually its fairly simple and very quick.
Step 1: Download the manual version.
Step 2: Open your EA folder, mine is : C:\Program Files\Electronic Arts\Warhammer Online - Age of Reckoning
Step 3: Locate or Create the "Interface" folder.
Step 4: Open the interface folder and there should be (if not go ahead and make one) one called Addons.
Step 5: open the zip file you downloaded and place the folder contents inside the Addons folder.
In the end the entire destination should read something like
C:\Program Files\Electronic Arts\Warhammer Online - Age of Reckoning\Interface\Addons\CraftingWillard
Scientia est solvo.
EGO sum Anonymous.
EGO sum Legio.
EGO operor non indulgeo.
EGO operor non alieno.
Specto mihi.