@Door321
As is ALWAYS the case with these things, by that I mean adaptations, its usually better to start with chapter 1 if you want the 100% story. The anime, since it falls into the modern 12-13 episode season format has to cut many things for time reasons. Having said that Noragami is a fairly faithful adaptation (I would say about 75% of the source material is included. MUCH MUCH better than many Lightnovel anime that often cut around 50%.
In Noragamis case season 1 even had some "extra" material in the end with the other War God - who is not in the manga.
Its also important to note that certain things the anime decided to do actually contradict the established "rules" of the manga later down the line in the manga - not blaming the anime, they couldnt know at the time it was made as this information comes later. Without trying to spoiler ill just say this: Nora (as a sword) fighting ANYONE really as she does in the "extra part" of season 1 I mentioned is well... it would have been baaaaaaad for Yukine if he actually fought her. And Yato does not split the heavens like at the end of season 2 because again... that would have been baaaaaaaad had he done that right then and there.
So long answer aside... the short answer is: Read from chapter 1. The art is gorgeous so its worth it.
@calmbreez
THIS is the original source. Its not based of a LIghtnovel like many modern anime are. So whoever told you about certain ships or whatever was having you on. The story is still going after all.