Heyo! (just a heads up, I trimmed your thread description above. Try to keep those on the shorter side so you don't crowd out everyone else's threads on the forums. ;) Common courtesy thing.)
If you're looking to write up some new SCPs and tales, it's a good idea to take a look at the newer stuff that's not related to SCP:CB (since the mainsite actually isn't affiliated with the game, our perspective of the Foundation'verse spans a much wider reach. We've got tons of material here not covered by the game to explore!)
If you're looking for SCPs that are a good example of current site standards, I recommend reading the high-rated Series II and III articles (SCPs with numbers from 1000 to 2999). There are many inspirational articles in Series I, but articles written six or more years ago are less likely to be up to current community expectations, even if they've got a lot of upvotes. Remember to pay attention to how old an article is when deciding if you'll use it as a guide or not; you can (and should!) check article age by clicking the "History" link at the bottom of a page, and looking for the page creation date.
So far as a starting point goes, everything you need to know to begin is in the How to Write an SCP Guide. Make a sandbox or go to the Ideas and Brainstorming forum to get your ideas polished up, and see where things go from there!