Common prepositions of place fall into 3 categories

AT is used for specific points

Let's see each other at the corner.

My house is at the end of the street.

You can find all the information at the top of the page.

I left your bag at the front desk.

I left my phone at home.

IN is used for spaces which are enclosed or have some form of boundary

I live in Italy.

My friend has a company, this is based in Paris.

The dog sleeps in its bed.

The wallet is in my left pocket.

Do you work in that building, in the city center?

ON is used when something is on a surface

The painting is hanging on the wall.

There's a dog on the mat.

We are walking on the floor.

Can you see what's on the table?