This is the first memory block you need to unlock and of course, the easiest of the five puzzles. Basically, you need to use at least one code block on the gaps to let your indexers cross.
Next, remove the first code block that is blocking the decoder beam. This will take down the first firewall. Head to the next corner and lift the Decoder Relay block and rotate it so its pointed side is pointed to the second firewall.
Before bridging the gap, make sure to start placing defense constructs along the way, preferably one near the yellow data stream, at least one on each corner, and one near the base. You can place the last defense construct in the middle. Now place a code block on the gaps and let the Indexers do their work.