There are lot of ways to get started & we will teach some of them
Mozilla Location Services
The Mozilla Location Service (MLS) is an open service which lets devices determine their location based on network infrastructure like WiFi access points and cell towers. This network based location service complements satellite based navigation systems like A-GPS. Combined these two approaches are one of the foundations for enabling context aware applications.
Documentation is one of the main contribution done to the community. Whenever a single learning is documented in a blog lot of people will love to learn from them. And also you can easily write blog post about Firefox, Firefox OS and write MDN articles all it needs in writing knowledge in any language.