Decide where you will build the barbecue. Remember the grill will be permanent once you build it, so take great care when considering its placement.
Lay out the first layer of bricks as a guide to help you picture the size of the grill. Use the metal cooking tray as a guide for size.
Mix the mortar using 5 parts sand and 1 part cement. Add water but just enough so the mixture is still stiff.
Remove the first layer of bricks and put down a layer of mortar. Replace the bricks in the mortar, using a level to make sure the bricks are level.
Repeat this process, adding more layers of bricks. Check with level once you have done five layers to make sure all layers are even.
Turn some bricks inward once you reach layer seven on the inner wall to act as support for the grill. Use the grill as a guide to make sure it fits snugly.
Add more supports with three courses of bricks to hold the cooking grill.
Add a professional finish to the outside of the grill by "jointing." Drag a concave jointing tool along the mortar gently to smooth it out.
Allow mortar a few hours to dry before using the grill.