Warcraft III Re-Reforged I Custom Campaign I Path of the Damned 3 - The Dreadlords Convene 

Hey, download the campaign which you would like to play from hiveworkshop first. Once is done put the file into your Campaign folder. Usually the path is My PC->Documents->Warcraft III->Campaigns. Boot up and log into the custom campaign within WC3 and you area ready to go.