Something like 20 years ago I used to be an Appleseed instructor. Much of my information may be out of date but some things never change!
The old style cotton or leather military sling is preferable to the nylon sling. Nylon is slippery and tends to move around while your trying to shoot. I used to bring a bunch of mil surplus cotton slings to loan to the students. You will need the wider sling swivel for those slings. The military sling is 1 1/4" wide. The typical civilian sling swivels are only 1 inch wide. You will want both swivels mounted on your rifle. Tech sights are very good but scopes are allowed and work better for most. The standard 10 round mags are preferred because the extended mags get in the way. Tube mags are a handicap. They can be used but your not going to like loading them while laying on the ground with everyone else waiting for you to get it done. Semi-auto rifles are preferable but a bolt action can be used. A piece of carpet can work as your shooting mat. 2 or 3 foot wide and 6 foot long is big enough for most. Ear and eye protection is very important. The person next to you may be shooting a 30-06. The program was originally designed for WWI era bolt action military rifles. Some locations only allow .22 rimfire ammunition.
Do not wear your self defense weapon on the firing line. We are very friendly with concealed and open carry but there are major safety problems created by extra weapons on the line. Safety is the most important thing for us and we have lots of safety rules you must follow.
I finally found the web site:
https://appleseedinfo.org/
Look around in there and you will find lots of up to date information.
Here is the best up to date information:
https://appleseedinfo.org/how-to-prepare/