In the top-left corner on the navigation bar press on "Discover"

You'll be directed to the search page

At the top, in the search bar, you'll be able to type your location

Press on "change" to edit where you search for volunteer work and indicate your location of choice

You can also find volunteer work via the map on the right of the search result page

Use your cursor to move the map around to the area you'd like to search

Press on "redo search here" to view volunteer activities in the chosen area