The Seaweed Method is a variant of the Columns First Methods. It was mainly created for fun and isn't very efficient. It was inspired by several methods (such as CFOP, Columns First Methods, Reduction 3x3).
1. 4 F2L Pairs
This step is very easy to do intuitively, although you could use one of the four algorithms.
Orient the four LL corners using at least 2-Look OLL. Don't mind the edges that may be flipped, white or both.
Permute the four LL corners using at least 2-Look PLL.
5. Last Eight Edges
You are now left with eight edges. You have to permute and orient them in any order.
Using the Seaweed method the way it is described above will solve the cube, but it will be slow and take a long time. There are multiple ways to improve your times with this method:
a. Setup Moves
The best way to improve is to use setup moves for the last step, as you would for Old Pochmann but with these algorithms.
b. More and faster algorithms
Learn all the useful algorithms. Try using algorithms that would solve a case that resembles the one you have for OLL and PLL to set up a better case for the fifth step. Also use some OLL (2x2x2) algorithms for OLL (don't use the ones that swap your F2L pairs though).
c. Practice the first step
Try solving F2L as fast as you can. Also try inserting pairs in the right spot from the beginning to get a very easy case or a skip on the second step. Become color neutral (at least partly). Look-Ahead is also crucial.
d. Pay attention
Try to identify as many F2L pairs as you can during inspection and where they should go. During Look-Ahead, try predicting which center permutation you will have to make. Predict where edges are going during the last step to flip them correctly beofre swapping them in certain cases.