what do you mean byUse at with the name of a place when you think of it as a point.

We use 'at' when we think of a place as a "point'. It means when we are talking about an exact, specific, direct, particular place.

For example, The man is standing at the bus stop.

Contrast this sentence with the following one:

Gayatri has been living in China for three years.

China is a country. When we think of a place as a large area, we use 'in'. Bus stop, on the other hand is a small, specific place. Hence, we use "at".