You should start with some "light reading" LOL.  First check out the Self Help Center, above right near the life preserver.  That will answer many of your basic questions, including photo guidelines, and ad guidlines.  You can post photos on Theme days and in Ads per the guidelines found under Discussion Board Guidelines in Self Help Center.  I included a link to the Ad posting guidlines below.  Next scroll through the last few pages of this board, as there are new folks almost every day asking questions and you will find some good answers.  You can also use the search function to look for a specific topic to see if it has been covered.  Just be sure to change the 30 to at least 300 in the day range.

And, of course you are welcome to ask any specific questions here.  There are many knowledgable people willing to help.  It is difficult to answer a general plea, since there is so much info  hope this helps get you started.