master thesis structure
Mosy probably, your thesis is not supposed to read like a collection of unrelated articles. Therefore, you will need one general introduction. It could contain information on


which components exist
how each component is connected to the whole
why components were separated as they are.


This does not preclude additional per-section introductions to explain more in detail what the upcoming section is about.

Proceed analogously for the conclusion and, of course, talk to your supervisor for any specifics.