How to make a cold compost pile: Throw everything into a pile. Wait.
Yes that’s a bit flippant, but it’s pretty accurate. And, it’s not meant to discourage you from building a hot pile. Hot piles have a couple of distinct advantages over cold piles.
For starters, you get compost much, much quicker.
And, a hot pile will kill weed seeds and pathogens, which won’t happen in a cold pile.
If you have a lot of plant material at once, you should build a hot pile. The benefits make the extra effort worthwhile. Build it all at once, maintain it, but don’t add additional ingredients.
But, if you don’t want to put in a lot of effort, or pay attention to strict proportions, you can still compost in a cold pile.
It takes a lot longer, but nature does most of the work instead of you.