Click on 'People' under Search to begin searching for people. Initially you need only enter some part of the name (if any) of the person you are looking for. However, if you click on 'advanced' you will be given more options, such as zip code, and orange.

Searching for projects is similar to searching for people. You first need only specify a name, but if you want you can narrow projects down by location and if they are recruiting or not. This is how you would find open positions of interest.