If you want to get alerts about a specific station(s), tap on the "Alerts" button on the station description screen:

Then switch on the toggles of the alerts you want to receive for that specific station: 

To manage or change your station alert settings, tap on "Me" on the bottom tab menu:

Scroll down in your profile view and tap on "Alerts"

To see which stations you have alerts set for, tap on "# Location Alerts Set":

-You can also set up general alerts for a certain radius to get updates about stations in your area

Which will take you to your list of stations you have alerts enabled for: 

Tap on the location name to manage your alert settings for that station

Make sure you have notifications enabled for PlugShare in your phone's settings to receive push notifications: