As with other games, you need to own the computer and this one is the largest to download from TeleBBS. See https://my-summer-car.fandom.com/wiki/Con-Line_BBS
for download instructions.
The actual game is not that hard. There's a manual in English at the beginning, but basically you can move your character with arrow keys which moves it slowly through the tiles on the map, and you have to pick up all the items there.
You can't see your character position initially, so you have to guess where you are by going in one direction and guess the position from the changing scenery.
The more you play, the faster you'll go and eventually you'll see your character position with a small blinking pixel and coordinates.
Once you find all the items, the Truth location will be somewhere in the square that is marked with the red coordinates – try to go through all the pixels to eventually find it.
The achievement pops once the end-game screen is shown.