What is the difference between occupation and job and employment and profession ?Feel free to just provide example sentences.

They are fairly similar in some contexts, but:

Occupation = what occupies your time.
Job = an individual piece of work or contract, or ("permanent job") an ongoing work at the same place or in the same role.
Employment is ... sort of the ongoing process of having one or more jobs to do (it's literal meaning is more or less synonymous with "use", "usage", "utilisation" ...).
Profession originally meant that you (at least potentially) were a "professor" - and that it had to be taught (again, by a professor). It's a funny word because it also sort of means that it's "what you say you are" (what you "profess" to be).