I’ve just got a big pile in my garden that I haven’t been turning. I was thinking of spreading it all out when we till here in the next couple weeks. Is that a good idea or no?
It depends on the state of decomposition and what the material is. For example, if you till in wood chips that are not fully composted, they will rob the soil of nitrogen which will be used to decompose the wood chips instead of feeding the plants. But you should be able to till in the "green" materials.
The condition of your soil also matters. I saw a YouTube video where a guy tilled in fresh wood chips into his soil because he needed to break up the soil now.
I have gone to an almost no-till method of gardening in raised beds. But I still have a small cultivator that will gently mix in my top mulch or compost into the top 3-4 inches of raised bed soil. There are many people that advocate the no-till method because you don't want to disturb the living system in the soil unless you have to.