Start by doing a search on google for swift tutorials and start with an introductory tutorial.
If you aren't much of a self learner then enrolling in a programming, IT or computer science course at your local educational institution is another starting point.
it sounds like you don't have any background in programming, so yes it will take a significant investment of time. 6-12 months at least if you are serious about it, maybe more.
Topic:
App & System Services
SubTopic:
Core OS
Tags: