composting is necessary because it kills pathogens and dormant seeds in the manure, to do it just check out a tutorial on how to compost manure.
I'm pretty sure you can do it by taking a big pile of leaves and grass clippings, and mixing it with the manure
this creates "black gold"
in order to get the full benefits, you will need to Amend the soil.
this will mean adding stuff like lime and/or powdered oyster shell, and other things that will help with the micro nutrients.
as the plants reach flower you may want to topdress with a high PK bat guano but make sure you don't skimp on the nitrogen
and as others said, be careful not to overdo the mix, and burn your plants. You can always topdress later. Consistency is very important too.
oh yeah wanted to add in that you may want to cut the black gold with perlite and peat or something like that, most soil mixes are 30% compost, 30% peat, 30% perlite/vermiculite, 10% earth worm castings