Approaching the genre, you have certain pieces of assumed background information covering the nature and purpose of dragons, warp drives, or shootouts at high noon, which are taken for granted by the genre conventions, and need not be explained for the reader anew.
You is approaching the genre. You have certain pieces of assumed background information. Background information is covering the nature and purpose of dragons anew. This was what this assumed. Background information is covering the nature and purpose of warp drives anew. This was what this assumed. Background information is covering the nature and purpose of shootouts at high noon anew. This was what this assumed. High noon are taken for granted by the genre conventions. High noon need not be explained for the reader.