First you get your PPL, then you build your hours untill you have around 150 hours. During your timebuilding or after, you start the atpl ground school and after finishing, you take the theoretical exams. After this you get your CPL/ME/IR and these may be done in different order. after these you are a commercial pilot and since you did the ATPL you have a froozen ATPL wich will become unfroozen at some point. Normally 1500 hours. If you want to instruct, you take a special course wich makes IT possible to apply for a job as a flight instructor teaching stalls and turns and all that. If you want to fly for the airlines you need a Type Rating on the plane you are going to fly. You can apply to an airline and some of these psy the Type Rating for you. Or you can pay for it yourself and apply to an airline that uses that plane.
This is the basic information you need to know about. There are different ests of doing this, step by step or all togheter non stop. There are many things to be Said about type rarings, schools etc so please read through this forum. You'll learn everything you need to know here and I know that there are professionals here that know a lot more than me. So search around!
Good luck!