What does "a" and "s" mean in a rubik's cube?

Question

Like i have this one algorithm [U'R B'R'U R'D²F U F U'F'D'U²BsLsD F] and i have no clue what to do when i get to the "BsLs". is there like a chart.

Answer 1

Go to:

http://www.cubestation.co.uk/cubenotatio...

Hope this helps!!!

ps: I think Bs is the middle layer at the back side!!

Just combine the layers and you should figure out something!