So I didnt find alot of help online when I wanted to set this thing up so I think I'll include what I learned
Top soil or Yard dirt
Wire lid and a towel
So first I rinsed down my terrarium with water and a cloth. Then I placed the topsoil in it. Make sure its completly organic with no additives. A ph of 7 should be good, if your bag doesnt have a PHjust be sure to check the ingridiants for any additives.
You can also use dirt from your yard. You can put it in the freezer for 24hours to kill any bugs that might catch a ride. Here add your worms if you have any. They help break down snail waste and help your terrarium planta grow. Then place your rocks and weeds.
I put plucked dandolion leafs and some random weeds from my yard for them to eat. The wire lid is to keep the snails in but the towel is to keep in the moisture. Cuttlefish bone is commonly sold in the pet isle for birds but works as a great source of calcium for your snails. Just break it up into bits and place them around your terrarium. Now add snails
now keep your snails moist and remove any rotting or uneaten food