accidentalsmallholder.net/forum/index.php?topic=82100.15
One of my posts in nthe thread give you a lot more detail ,. you only need straw bales & a gentle liquid manure to get theh bales breaking down / composting .
Wrapping the bales in plastic sheet astraight after givening them a good wetting will help to get them sweating , Once you can see they are rotting down intop compost it helps tremendously but you'll need to remove the sheeting when you plant up or you can roll the sheet back down to the ground & weight it down before planting & feeding with plenty of the same .
Many of the American guys In American sites thoughtthat they had to earth up on top of the bale ......There is no earthing up to do.
I used to use a long pointed 2x 2 2 length of pointed wood to poke a 15 " deep planting holes down into the composting bales then drop a chitted spud down each hole & push some composting straw gently down the planted up hole .