The bathroom in the new apartment was in great shape overall, except there was no bidet installed. I could've called someone, but to save the service fee I decided to install one myself, a bidet I'd ordered from AliExpress for about 60,000 won.
Removing the existing toilet seat
First I took off the plain toilet seat that was already there. Feeling around under the bowl, there are plastic nuts on both sides that you can loosen by hand, turning counterclockwise, no tools needed. Once the nuts are off, the seat lifts right off.
Shutting off the water and connecting a T-valve
I shut off the angle valve on the wall next to the toilet, then used a wrench to disconnect the supply hose going into the tank. I connected the T-valve that came with the bidet where the angle valve had been, splitting the line into one for the toilet and one for the bidet. I wrapped the threads with Teflon tape, and this time it sealed cleanly with no leaks.
Mounting the bracket and the bidet body
Once the water side is done, the rest is just assembly. I set the bidet's mounting bracket over the bowl's existing seat holes and used an electric screwdriver to tighten the bolts holding it in place.
With the bracket secure, the bidet body slides into place and locks in.
Connecting the hose and testing
I connected the remaining port on the T-valve to the bidet body with the included hose, plugged it in, and turned the water supply valve back on. Once the bidet's light comes on and you hear water filling, it's installed correctly.
Wrap-up
The whole thing took under 15 minutes. Aside from the bidet itself (60,000 won), there were no extra parts to buy, so there was no real cost to worry about. Having a warm seat every time I sit down turned out to be more satisfying than I expected. I should've installed one sooner.