Instantiate in Start

Very early days of making a roguelike game, I have a script that generates a grid of tiles for the player to walk on. The script Instantiates the ground tile in Start() and everything works OK.
So, when I was writing a new script to generate the layout of the rooms, I used the ground tiles to represent rooms, and used very similar code, and while it seems to work, it is giving an error saying Instantiate is “not allowed from a MonoBehaviour constructor (or instance field initializer), call it in Awake or Start instead.”
Now, it is in Start, so I don’t know why it’s giving me an error. It doesn’t seem to affect anything but I wanted to make sure I’m not doing anything wrong, and to know why the error is even there.

Nevermind, I goofed. Will delete this