Gamecube Emulation:
There's nothing special you have to do. You just need to dump .iso or .gcm from your Gamecube and tada! You have Gamecube emulator with your legally dumped .isos.
About memory card saves: if someone shared memory card with you, just put it at User/GC/"your region"
Wii Emulation:Wii emulation have some problems for users so I'll explain. To emulate Wii first you need to dump
masterkey.bin file. Every Wii disc contain this file so you can simply make a copy of it using your Wii for your Dolphin then use it for every revision you play.
Don't ask masterkey.bin from other users! It's illegal. You need to own your own Wii.
Second you need to put masterkey.bin file in Sys/Wii folder. I think it's not too hard.
About saves: if you shared you save file for Wii and you don't know where to put it, first you must do is at least play the game you wanna save for in order for folder "title" and "tmp" appear in User/Wii. Then put your saves here (usually it is User/Wii/title/00010000)
About ini's: if someone shared .ini (GameConfig file) for you just put it at User/GameConfig.
Dolphin emulation:Some games may not run with default settings, so try different configurations like disabling "Optimize Quantiziers" or enabling hacks in OGL plugin, etc. If the game don't work, you can always get help from other users or other forums (highly recommended dolphin-emu forums).
How to run debugger in Dolphin:All you need to is put "-d" at the end of command line to DolphinWX.
Just like this:
or
Just create shortcut of Dolphin with -d at the end.
Then follow instructions that someone said you.