Step 3 - Solve as a 3x3x3
For this step, solve as a 3x3x3 using whatever method you prefer. There are a few things that could happen in this step that won't happen in a typical 3x3 solve so I'll address them here.
Solving the Cube
Step 1 - Solve the first three layers
Solve the first THREE layers using whatever method you prefer. The only differences here are that you will have little or no inspection, so if your method relies heavily on the 15 seconds of inspection before a solve, it will affect your time for this step. Also, if you use edge control before proceeding to the last layer, 50% of the time you will see cases that you haven't seen in typical 3x3 solves.
Step 2 - Orient the Last Layer
In 50% of your solves, this step will not be any different than a typical 3x3 solve. In the other 50%, however, you will have what is known as OLL parity. You can fix it with the alg below.
Step 3 - Permute the Last Layer
In 50% of your solves, this step will not be any different than a typical 3x3 solve. In the other 50%, however, you will have what is known as PLL parity. You can fix it with the alg below.
Here are the algorithms for the OLL parity and PLL parity and some shortcuts that may help you save a step or make these cases easier for you.
|Rw U2 x Rw U2 Rw U2 Rw' U2 Lw U2 Rw' U2 Rw U2 Rw' U2 Rw'||If you need to flip three edges, It is recommended to put the solved edge in the back so that you wind up with an "Edges Bar" OLL case instead of an "Edges L" OLL case. There are fewer of these cases and they tend to be a bit nicer.|
|r2 U2 r2 u2 r2 u2 [U2]||This will essentially swap two opposite edges without affecting orientation.|
|(R U R' U') r2 U2 r2 u2 r2 u2 (U' R U' R')||Use this when you want to specifically swap two adjacent edges. Notice that it is just the PLL parity alg with a setup move that gets undone at the end. You could also use (R2 D' x') as a setup move.|
There are a few special cases that may look confusing at first or may save you a step. I'll list them soon.