How To Lay Cement?

Cement is a component of concrete so you are really placing concrete.
Not knowing what you are building but the first step is to build the forms to hold the concrete until it sets.
Next, you need to mix the ingredients (cement, sand and stone and water) using as little water as possible to make it a stronger product.
After finished placing, you need to keep the concrete damp by covering with wet burlap and keep it that way for about 7 days while it gets its initial cure.
Keep loads off it for as long as feasible because it will keep developing strength for a long time.