Easy if you fit poly bushes, need tool if fitting stock.
Unbolt axle at the pivot bolts and shocks, disconnect brake pipes. Drop axle off. Cut old bushes through open voids then cut the sleeve out with a hacksaw. Lube up the poly bush and hit it home with a rubber mallet or Metal hammer and a lump of wood. Bolt it all back together and bleed brakes.
It's all the same if you are fitting standard bushes apart from pulling new bushes in with the tool.