First thing you want to do is find a suitable printer. Generally it will be a slightly older model, and you will want it to be for a few reasons.

1.) The ink "security/drm" will likely be defeated

2.) There will be support from these CISS kits for them

3.) There may be aftermarket supplies of things like the printheads or the sponge material used in the Service Station.

I can't stress this one enough, make sure the printer actually works prior to you modifying it. If it's new in box and never has had ink within it might be the only time to ignore that. If the printer has been used, make sure using whatever means necessary that the heads in the printer are not clogged. You don't want to start out with failure. Don't waste good money chasing printers that ended up in a thrift shop for a reason, it's not worth it!

Not all CISS kits are the same, be on the lookout! If your kit includes a drill bit attached to a screwdriver handle, avoid it like the plague! That means they are going to have you drill into an original cartridge to supply the ink. These kits are generally even cheaper than other full kits. Look for the most well polished one that has the most favorable reviews, it will improve your chances of success

Many CISS kits offer a universal kit, you want something tailored to the machine you are going to modify, make sure everything is in order before you order. There may be steps that seem silly or overcomplicated, take that into account.

Your CISS supplier will likely use the path of least resistance in their kit, but this can also have the negative impact of making certain parts of your printer or all-in-one unusable or clunky to use. In my case I was worried about the scanner being impeded by the ink tubes, and even worse, the routing they wanted me to take would have likely pinched off the ink supply tubes and caused a blockage. I decided to cut a hole in my printer (Since I didn't have much money into it, and it was out of warranty for sure), to allow the ink supply tubes to go unkinked to the outside.

Your kit will likely have air bubbles in the ink supply lines, use whatever method you can find to move the ink. Also your printer will have residual ink inside the head in most cases, so you will want to purge as much of it as you can through the printer until you get to the replacement ink before you leave it unattended.

Use any diagnostic means at your disposal to make sure that the print quality is good, that ink isn't dripping inside the printer or on your paper. Searching "Service Mode" for printers sometimes gives you a secret konami code or procedure you can enter to get into service mode and allow you extra controls or diagnostics of the printer. Keep in mind a lot of these menus also have ways to brick the printer, so be careful and never do anything inside that menu you have not read up on or know what it will do!

Doing this will void your warranty through most manufacturers of printers. It's a sad fact of the world we live in today. Even though there have been many court cases on third party ink, many lost by the printer companies, unless you are a real glutton for punishment, you will not want to try to deal with a printer warranty if your printer fails after doing this mod. Follow these procedures at your own risk! If you end up with a twenty thousand dollar desk ruined by 600ml of ink, or any other horrible outcome (the printer calls your mother horrible names for an instance) I am not responsible. Thanks and I hope you found this useful!