ADAAmazonia New Version 2 Aqua Soil for Aquariums 9L

what tank size does this fit? I have a 40 inch length on 15 inch width. would this be enough?

Can I add it to an up and running aquarium?

Since this in the beginning causes high ammonia levels should I wait until it has a normal reading to plant plants?

Can this be using for the Walstad method?