Step 1: Prepare the tracks and parts as per the above picture.

Step 2: Connect 2 "L" tracks together.

Step 3: Connect another "L" track to the previous 2 "L" tracks as per photo above.

Step 4: Connect another "L" track to the previous 3 "L" tracks as per photo above.
Step 5: Repeat step 1 to setp 4 three more time to develop 5 sets of 4 x "L" tracks.