You can change on the main page as the photo. Click on the '+'
Or here is the direct link to the page 
https://www.fishingreminder.com/user/addlocation

You will need to zoom in to the location.

Have both :)

You can have as many locations as you like.

As Dazzling79 says, just select the location you want either by typing the name or selecting on the map. Then click Add Location. Then your new location will appear on your drop down list of locations.

You can then select any location on your list to be your "default" location. So say you live in Canberra but want to see what is happening in Batemans Bay, it is just a click.

Which ever location you have selected as your "default" is where your email reminders and weather etc will be based on.

I have about 100 locations on my list...:)