Oh, best way is to cut down the nettles- a little scythe is easiest. You can always just pick them or pull them up, but you'll need thick gloves for that! Lay them out on something to dry- I use a hurdle laid flat on top of bricks so that air can circulate underneath, but a pallet would do the same job. Just leave them outside for a few days in the sun to dry. Or, you can just tie them into small bunches and hang them up in a shed to dry. If you do that, make sure they are in small bunches or they can start going mouldy.
You can dry rosebay willow herb as well for the goats.
Beth