The Haynes 'The Caravan Manual' will tell you how, if you can't buy one local then contact your local Library some hold Haynes workshop manuals for various vehicles including caravans and motorhomes. I borrowed mine from the library.
FIRM LEVEL GROUND & AXLE STAND/S
Sorry but it's 'Elf & Safety speaking' Firm level ground and put an axle stand under the wheel your working on don't trust a jack espcially if you have to bang the drum to get it off. If you've done car breaks then you can do caravan breaks. Just take digital photos of the brake drum assembly once drum is off then you won't forget how it goes back together like I do.
Nobby, March 2008