land snail setup advice

Hi, I have a fish tank that I'd like to use for a land snail, what's the best way to make the lid ok for a snail? I'm thinking of attaching some kind of cover so snail can't escape but it obviously has to allow for ventilation so I'm not sure what would be best to use. I thought maybe a plastic sheet with holes ? Or would that cause issues ? I dont want to get a different tank ideally as i was given this one and its a perfect size so wouldnt want to spend money on a different one unless i absolutely had to. Also what would be a good site to get everything for the setup, or is it recommended to get things from a petstore? I'm not gonna rush into getting a snail until I've got everything perfect so all advice is greatly appreciated, thank you x