Drying chillis is a great way to preserve them for future use, my favourite way is to make a ristra, a guide to this is coming very soon.
Once dried you can leave the chillis whole or grind them up into chilli flakes or chilli powder, they give a lovely deep flavour if used dried or a slightly more mellow flavour if you re hydrate them in water first.
In the mean time if you would like to dry your chillis there are 2 ways i would suggest:
The first is to put your oven on a very low setting say 50 degrees, place the chillis on a baking tray in a single layer, place in the oven and bake for a couple of hours until dry, turning occasionally.
The second method is to simply leave them on a plate on a light and airy windowsill, making sure they are dry and any moisture is wiped away, this takes longer but it’s a great process as you can see the chillis drying out almost daily.