Step 4.
Place a 4x4 brace at each end of the 68” 2x8 as shown above.
Fasten it with 3” star head lags.
Step 3.
Place the 68” 2x8 on the bottom of the rock wall and center it.
Fasten it with 3” wood screws.
Step 2.
Start the assembly with the rock wall and a 68” 2x8.
Step 1.
Begin the assembly by locating these components.