...No one is answering his questions. Even though you should find the answers out YOURSELF, I'll be a nice guy to you just because you are new to the game.
Back in the game you can Z-cancel, but now it's L-cancel. The concept is the same. Just simply hit L/R right before you land after doing an aerial attack. JC means Jump Cancel, which means you can perform a grab with less lag. Simply hit X/Y or Up (jump)RIGHT before you try to grab someone. Now Wavedashing is a more advance technique for a new guy to do, but here's how to perform it: I suggest first pratice with Luigi, but since your game is new, use Mario. Before going into REAL WDing, try air dodgeing first. Just hit L/R in the air to airdodge. After knowing how to airdodge, try how to directional airdodge. Meaning using the joystick to control which way you want your character to airdodge to. After that, try to airdodge DIAGONALLY (downleft and downright). Not directly to the left, or directly to the right. WD is technically a really quick airdodge with directions. In order to do that, you also need to learn how to short hop. I'm assuming that you know how do it, so I won't go further with that. And now, try to SH, then QUICKLY hit L/R diagonally to the direction you want.
This takes a lot of pratice. Personally, it took me around 1-3 months to master or perform a WD fluently.
Ok. This is getting long. I hope that helped, and good luck. Keep searching for answers FIRST before asking questions. Oh, and also PLEASE NOT to double post :/
Lights out.