The first leaves are starting to drop so it’s time to make leaf mould. The usual recommendation is to build an enclosure made from chicken wire and just pile the leaves into it. A few years back I did a trial of a wire enclosure and a builders bulk bag, the kind used for delivering 1 tonne lots of sand etc. After a year the material in the big bag was useable but that in the wire box was far from ready. I have also used old pallets lined with cardboard with the top open to the rain.
Leaf mould is just what it says, leaves going mouldy and rotting down, it’s a fungal process so the leaves need to stay damp. Having an open sides means they dry out and the process slows down. Using a closed sided container really speeds up the rotting and can produce leaf mould in a year but it does depend on the leaves as some take longer than others to rot down.
Leaf mould is useful in the garden as a low nutrient soil conditioner. I use it in the autumn on carrot beds which do not need fresh fertliser. Some people add other stuff like grass clippings which speeds up the process but gives something that is likely to have more nitrogen. Personally I use just leaves collected locally.
The other controversial subject is whether the leaves should be shredded or not. I have done both in the past and the shredded leaves certainly rot down a lot quicker. Using a vacuum shredder also makes collecting leaves easier.
Finally, when the leaves really start to drop invite your friends round for a leaf gathering party. Feed them hot soup and homemade bread and have some fun.