Gadget - OS

Hi ,
I need to learn Linux codings , but no clear about the where to start . I'm looking to make gadget that can be useful for students . But i struggled where to start . As you know android is on linux base , planning to use it on that gadget also , but with modifications that matches the environment . Can anyone please suggest where to learn and what to learn , i'm zero in coding and programmings but exited and very much interested to learn .