City Searches

Here is the website: https://thestuffstop.com/

Want to be able to search for organizations based on their state and city. On the right side-bar toward the bottom you will see the states parent categories and the cities child categories of the state. The ideal way I want to do this is for a person to click on a state and go to a page that listed the cities. Then they could click on the city and go to a page displaying all the posts for that city & state, rather than going right to the posts as it does now.

Can anyone help me figure out how to do this?

Your help will surely be appreciated.

Thanks in advance!