1) Load up a tutorial world, once loaded in press "b" to skip tutorial.
2) Run straight through the tunnel, down the staircase and take your first right.
3) Now we are at the brewing station; coordinates (X:5, Y:79, Z:41), open the chest behind the brewing stand and collect the "(10) glass bottles", "(10) Nether Wart", and "(10) Blaze Powder".
4) Turn to your right and use "left trigger" to fill "(3) Glass Bottles" with water turning them into "Water Bottles".
5) Turn around and run to the entrance of the brewing stand area, turn right and walk up a small set of stairs, turn left and then down a small set of stairs, keep walking straight through the villager area and take a right when entering the farming area just after the villagers.
6) Now we are at the fishing station; coordinates (X:-57, Y:78:, Z:-70). Open the chest and collect the fishing rod.
7) Turn right and walk to the end of the dock facing the water, use "left trigger" to start fishing. When a fish has been caught, your lure will dip up and down, once this is happening use "left trigger" to catch the fish. Do this until you catch a "Puffer Fish".
Now that we have a caught our "Puffer Fish" we have all the necessary ingrediants to brew the "Potion of Water Breathing 3:00".
8) Run back to the brewing station; coordinates (X:5, Y:79:, Z:41) and place "(10) Blaze Powder" into the upper left corner for fuel, "(2) Water Bottles" in the bottom left, "(1) Glass Bottle in the bottom right, and then "Nether Wart" in middle top, once the "Nether Wart" has brewed, then place the "Puffer Fish" in the middle top.
You have now succefully brewed a "Potion of Water Breathing 3:00", go jump in some water above your head, drink the potion using "left trigger" and wait (2) minutes for the achievement to pop!