How to customize a Google Map?

Question

JavaScript

How to customize and add a Google Map to the site?
only interested in custom markers and blocks with a description of these markers
here is an example of a map

screen

here is an example block

screen

I created the map, imported the cities that need to be selected via a CSV file. (Marks appeared on the map)
What should I do now?
Perhaps the question is quite simple, but this is the first time I have encountered a similar problem, so I'm sorry)

Answer 1

only interested in custom markers...

infowindow