How can I build a retaining wall with blocks?

To build a retaining wall with blocks, first, prepare the area by leveling the ground and digging a trench. Then, lay the first row of blocks in the trench, making sure they are level and secure. Continue stacking the blocks, adding gravel and soil behind them for stability. Use a layer of geogrid for added support if the wall is over 4 feet tall. Finish by backfilling the wall and adding a capstone for a polished look.