You have to travel into the past for this step. There are 12 panels spread around the spawn area, the mudpit temple, and the minecart area. It is simmilar to Step 3, except of stepping on the panels, you have to knife them. When you have all 12 panels lit up, over by the minecart gate, out of bounds, you can see some sort of snare trap. You have to blow up the snare trap with an explosive, such as a Monkey Bomb. If done correctly, your character will say that it has worked, and you will return to the present.
After completing Step 9, there is a radio found near the Minecart gate on a barrel, stating a code, which is "16, 1, 3, 4". You have go into the past for this to work. After you have gone to the past, you will have to go into the mudpit temple and set the dial to their corresponding numbers. After this is done, your character should say that the code worked. If done correctly, you will have a diamond appear above the mudpit temple, signifying that you have completed this step.
After the previous step, in the present, by the right side of the stairs leading up to the Pack-a-Punch Machine, on the floor by the statue you will find a radio. This tells you that Brock lost his bag of Dynamite somewhere while being chased by zombies. You have to find the bag of Dynamite.