Many people in this forum would not recommend the use of youtube tutorials to mod your wii as they may not take system version into account and can be incomplete forcing you to make a mistake and brick your wii.
basically there are 3 steps to modding the wii (which I presume you have already done?)
1.Run the hackMii installer either via the sys settings or the memory card menu, then install DVDX, Homebrew channel, BootMii as boot2 (if you can) and BootMii as IOS (this doesnt hurt)
2. copy the necessary apps and wads and trucha patch the ioses
3. install the wad files for cios 202, 222,223, 224, 249,250, etc using wad manager
Basically there are links to decent soft modding guides on here which are very easy to follow. You should really follow them as opposed to doing it blind with a youtube video.
One word of advice and I cannot stress this enough, is to backup your nand to sdcard using bootmii when the wii starts. Use the power buttton to move through the options and reset to select or use a gamecube pad. You need the cogs icon and then the icon showing the chip with the arrow comming off it (I think its green). Just let it run and backup your nand before messing with the system ios files. That way if it bricks or you make a mistake your can recover it.
Failing that if you have followed all the steps correctly, still backup your nand anyways and try to put something like neogamma on your sd card and run that from homebrew channel and see if that works. you should also be able to install a channel short cut for neogamma to run it from the sys menu. I dont think a DVD-R game will show up on the disc channel unless you use cioscorp but I wouldnt recommend it as its not for noobs and it easily bricks wii's!
If I were you I would check your modding steps by looking at the guide here:
http://gbatemp.net/index.php?showtopic=171901
Backup your nand first after installing bootmii though just in case. Also pay attention to your sys menu version you could be on 3.x-4.1 or 4.2. The guides are different depending on what version of the system software you have. You can find this in the wii settings.
Get NeoGamma backup loader from here and copy onto the sd card (place it in the apps folder):
http://gbatemp.net/index.php?showtopic=158884