shed foundation

So I have bit the bullet and ordered everything I need to create a base for my new shed. However I am a bit worried I may have ordered to much "Grando Tarmc to dust" https://www.diy.com/departments/tarmac-grano-dust-bulk-bag/165422_BQ.prd Each bag is about a 1 tonne and I have ordred 2. The...

ok so finally I have decided to lay a foundation my self using this method: I have calculated for my Garden I need 3.1 Meters by 3.95 Meters and will use 95 slabs 400x400. I am going to this 6mm to dust https://www.diy.com/departments/tarmac-grano-dust-bulk-bag/165422_BQ.prd I will need...