Fill the holes in the concrete block by pouring soil or concrete inside. Add water to premixed concrete and mix it in a bucket or wheelbarrow with a shovel or trowel. Follow the instructions for the ratio of premixed concrete to water.
Smooth the top of the concrete block with a trowel after it has been filled. Ensure the block is level.
Apply concrete adhesive liberally around the top of the concrete block. Use a brush or caulking gun, depending on the type of adhesive you are using.
Position the concrete cap on top of the block. Align it so it is even and in the desired position.
Fill in any spaces and cracks with mortar.
Wipe off any excess adhesive or mortar with the trowel.