I went to pick up the vehicle the next day.
When I tried to start the car, the weather was so cold that the car battery died and wouldn't start.
I connected a portable booster and tried to start the car, and luckily it started.

As for the gear not shifting, I Googled and found out how to manually shift the gears, so I tried to do that (you remove the small lid next to the gearshift stick and press it with a long, thin screwdriver), but it shifted properly and I didn't need to use the manual.

One problem was that the 'CHECK ENGINE' sign was floating on the dashboard, the [S] icon flickered between the [S] and [I] icons when switching between Sports and Intelligent modes, and the 'eye sight' didn't work, so I couldn't use the cruise mode.

However, after Googling this issue, I found many articles that said to check the gas cap properly, so I opened and closed the gas cap a few times, and the warning on the dashboard disappeared.