I failed woodwork and I built a whole bank of compost bins without plans for free.
You do not need compost bin plans. It’s not as though you intend to make a feature of your compost storage bins. They do not need to be particularly beautiful or even square.
All you need are pallets, screws, nails and a few pieces of timber to fix your pallets together. You can pick up wooden pallets for free because they are designed to be thrown away after just one use. Use a full-sized large pallet for the back of your compost bin and smaller euro-pallets for the sides. Saw a large pallet in half for the front because you need to be able to climb in easily.
If you need additional compost bins just attach them to the first one. If you have room you do need more than one compost bin. You need a current one to be filling, one that is maturing and an empty bin to turn your full bin into.
You can dispense with the fronts if you want to but they do keep your compost tidier. You do not need to treat your pallets with preservative or paint, just replace them when they rot. Preservatives or creosote will contaminate your compost and potentially any crops you grow using that compost.
I have separate bins for leaves, also made from pallets, because leaf mould needs anaerobic conditions to form, so you never turn leaves that are rotting down.
Dead leaves are your brown compost that in an ideal world you mix 50:50 with green compost. My problem is that all through spring and summer I have lots of green compost from grass cuttings and it is only in autumn that I have any appreciable amount of brown compost. Composting my leaves separately means I can use the leaf mould on my rose garden. My other compost still rots down perfectly well, even though it is not the perfect half green and half brown compost that compost obsessives insist on.
Plastic compost bins are usually a waste of money. They are not strong enough or large enough to ever reach the required temperature. I do have a collection of wheelie bins that I use for throwing weeds into. I leave these for three years and the weeds turn into compost, but I only use this for deep down soil improvement.