The first time you log on with a new browser you have to do that with all password protected sites. After that it should be automatic if settings are right. To check: At the top left of the screen:

Tools ... then Options ... then Security

There is a box "Remember Passwords for Sites" that should be checked. Close box.

Then when you log on and put in a password you will get a pop-up box asking if the password should be saved or remembered.