i am making a horror game about an abandoned asylum, i have made the front garden to the asylum and i used like 100 cubes to make the terrain because i didn’t know how to use it well, now i have added the one big terrain, when i spawn in the game, it spawns me to the bottom right corner of my map which makes the game completely unplayable, and when i try to jump away, it just spawns me back to the same corner as soon as i land

I assume you mean a real Terrain object. Try moving the terrain so that the place you want to be is under your character controller.