I'm a homebrew newbie. I just started using homebrew like mere weeks ago.

I've seen some homebrew videos where the guy opens the homebrew channel and instead of loading from the SD it loads from an IP, most likely his computer. How do I open apps remotely? Or know if I can even do that?

You use WiiLoad. You can find information about it on the Wiki. Basically, you download a program to your computer, open HBC on your Wii, press home to get your Wii's IP, then enter it in the program and select the homebrew and press send and the Wii will recieve and launch it.

VERY helpful tool for coding, so you don't have to do the sd card shuffle dance back and forth to your computer and wii OVER AND OVER.

And you can also use it to play homebrew that you don't have / want to put on your sd card.

WiiLoad goodness!