I'd like to use Google Maps api to set up a transit point using route search.

I want to be able to use the place library to search for my own routes in the markers displayed in the range, but I have set the start and end points, but I can't implement the transit points between well.So I'm thinking of taking the name or latitude longitude that I set for the marker that opens the infowind and setting it as a transit point.

Please tell me the name of the selected marker or how to obtain the latitude and longitude.If so, please tell me the best way.