What is a conjunction? It is a particle that connects words, phrases or clauses. They are usually called discourse markers, because they join sentences.
1) Coordination Conjunctions: give equal emphasis to two main clauses. Use a comma before the conjunction.
example: John plays in the garden, and Jan makes his homework.
2) Correlative Conjunctions: Connect two equal grammatical items (eg. nouns). Don’t forget the parallel structure.
example: Not only did I finish my work, I also had time to do extra.
3) Subordinating Conjunctions: Connects a main clause with a subordinate clause. The transition indicate a time, place or cause and effect relationship.
Example: I drank a glass of water because I was thirsty.