Installing just Haxchi is perfectly safe and will give you simple channel access to other homebrew programs without the need of the browser exploit anymore.
Installing CBHC though is FAR, FAR more dangerous but will allow coldboot into patched menu/homebrew.
Please ONLY INSTALL THIS if you already have the normal Haxchi installed and know that it works perfectly, just install it over your existing Haxchi installation, again, DO NOT INSTALL IT from a freshly downloaded, never started/tested game or you may brick. Also ONLY INSTALL THIS IF THE DS VC IS BOUGHT FROM THE ESHOP ON THAT CONSOLE AND ON NAND AND YOU HAVE NO USB CONNECTED WHEN USING THE INSTALLER.
If a new CBHC version comes out you can just run the installer again and let it overwrite the existing CBHC installation, same rules as on the first installation still apply.
Installing this will execute the DS VC of your choice directly on system boot - giving you a direct coldboot exploit, the features you have after installing it are explained down below.
After installing it you better go ahead and set up some DNS server protection to block potential future system updates, while CBHC will fake the system version to 99.99.99 it still adds another safety factor just in case
Disable standby for extra safety, again just in case
NEVER try to delete/install over the DS VC you used to install since it is now basically your system menu so if you break it your console bricks too, there are several protections against overwriting, moving to usb and deleting, but you should still not try your luck and trigger that protection over and over again, just generally be smart about it, I am not responsible for your dead wiiu because of user error.
Do NOT do a system format while CBHC is installed and autoboots your system or you will brick because you delete CBHC in the process
Do NOT delete the user profile you used to buy the DS VC since that will make it not properly licensed anymore on your console.
Also there still is a myth going around it will brick if you move its icon in the menu or put the icon into a folder; that is false and is perfectly safe as it is only a visual change in the system menu.
Anyways, enough of that - what can this actually do when installed?
It offers a basic menu from which you can boot into:
The system menu which will get full signature and region patching and support this ftpiiu-everywhere version; CBHC comes with its own sysnand CFW included.
You can boot into the .elf version of homebrew launcher.
You can boot a fw.img or Mocha CFW on your sd card which could be useful for rednand and if you really need to connect to wupserver from a pc, but thats really only interesting as a developer. For pretty much anyone the system menu setting (which uses the included CBHC CFW) is enough, on top of that using Mocha or fw.img for sysnand can lead to bootup problems and takes far longer to boot so please just dont do it, I dont know how often I can repeat that point anymore.
You can boot into the vWii system menu or the vWii homebrew channel, also if you hold down B on boot you will automatically boot into the vWii system menu as the menu originally did
If after installing CBHC no menu pops up when you turn on your console then you may have run into the very rare case in which CBHC did not properly install and your Haxchi installation still runs, in this case just go back into the homebrew launcher and try installing it again.
If you want to automatically go to any of these options just enable the autoboot option for it.
The menu controls are very simplistic, up/down to move the cursor and A to either select the option or change the autoboot option, you can control it using the gamepad or any wiimote, classic controller or wiiu pro controller OR if you are really desperate the the "sync" button on the console itself will work too - click once to move the cursor down and double click to simulate what A does normally.
Once autoboot is set up you can easily cancel it by pressing the home/sync button while the "Autobooting..." message is shown to get back into the little menu and change your settings or launch something different from there.