The Plain and simple conflict of interest guide (PSCOI) is an essay written by Wikipedia editors to provide a proactive interpretation of the Conflict of interest (COI) guideline. The official guideline is mostly a collection of "dont's" but the unofficial PSCOI advises some "dos".
The key points of PSCOI are to disclose your relationships, to understand the nature of your COI, and provide actionable advice for those with financial interests in a given page.
For such editors, PSCOI advises it's best to create a username, understand the Notability guideline, write a disclosure statement, write draft language as neutral as possible and supported by quality sources.
The essay also includes answers to common pain points, like what to do if your company's article is deleted. PSCOI doesn't answer every possible question, but it does a pretty good job of keeping it plain and simple. Still confused? Next week, more focused advice.