In this video I got the information about coordination and subordination.  
Coordination has to do with connecting ideas of equal importance, Subordination has to do with connecting more important ideas and less important ideas.
Independent clause it's simply a complete sentence a sentence that has both a subject and a verb so this sentence can stand alone and that's why we call it independent as opposed to dependent, Example : Susan forgot to set her alarm.  Susan is an subject and forgot is a verb.
Coordination connects equal ideas and subordination connects in equal ideas. Example : Susan forgot to set her alarm and Susan (coordinating conjunction) like and and we still have our two independent clauses but we have this coordinating conjunction telling us that both of these ideas are equally important on the other hand we can also connect ideas where one idea is dependent on the other idea so in this sentence Susan forgot to set her alarm because she was tired we still have two independent clauses Susan forgot to set her alarm and she was tired but we're not joining them as if they're equal we're joining them as if the reason she forgot to set her alarm was because she was tired.
A few examples so on one side we have our coordinate adverbs and these are words that connect equal ideas so words like also, besides, furthermore, however, etc and this is not a complete list but we probably get the idea these are words to add additional information that is equal on the other side we have our relative pronouns and these are words that make clauses dependent so we have words like that who, whom, whose, and which.
If we still have two independent clauses within this sentence but one of them the one attached to our relative pronoun has been moved into the middle of the other independent clause so our two clauses would have been Susan forgot to set her alarm and Susan was tired but because we're using a relative pronoun we're going to stick that relative pronoun right next to the subject of our first clause so we'll know who it's referring to and in that way one independent clause gets subordinated into this sentence and in fact actually put or shoved right in the middle of that first independent clause so hopefully this has helped you understand a little bit about coordination and subordination and how they both join sentences but do it in two different ways