Your horse can't swim across the water. Use your agent to build paths to connect the islands so that you can ride your horse across.
Since there is no one solution to this puzzle, there is no specific solution.
The easiest way for students may be to program their agent to build bridges between the islands one at a time.
Some students may just have their agent build a path to the X and Z coordinates of the opposite gate, bypassing the islands altogether.
Similar coding strategies to the Broken Bridge puzzle will work here.
The most common issue students encounter is trying to build a bridge outside of the area marked by the buoys. There is no way to build one straight bridge across. At some point, the path MUST turn.
Students with advanced programming skills may figure out how to program their agent to detect water blocks beneath it and place bridge blocks down if it does, or to use the wall builder to connect blocks, but those solutions are outside the scope of this program.
*Note: If you are not comfortable with the builder command, create a bridge3 command in the same manner as bridge1 and bridge2 instead.