Add your API key in the box at the top of the page, set your 'Minimum Money on Hand' (below) to however much you want someone to have before you mug them and then get mugging.
If you have any questions check this page.
UPDATE:
Pink rows imply they are in a clothing store.
Red rows imply they are in hospital.
Blue rows imply they are abroad.
The minimum number of $ you want your target to have on hand. (Example: 20000000)