What substance should I use to stratum my landscape? We have multiple places around our house where on earth we...

We have multiple places around our house where on earth we put bricks on top and I noticed it is kinda slanted. What would be the best bits and pieces to make it horizontal?
Answers:    im a landscaper for a company in montana. what we use for the plinth of bricks and rocks is sand, or realy small gravel. but sand works best. just verbs down about an inch lower than the bricks and crowd that inch with sand or the gravel. and somthing else that looks debonair is fill the gap between the bircks with the sand or gravel as resourcefully.
If you can afford concrete, and that is what you want, stir for it!
It will make a nice Patio or passageway.