That's why you don't use your real name on a forum (and you never post identifying information like address and phone numbers). <g>
A pst file is the data file outlook uses to store the email, calendar, contacts etc in - they are called pst files because that is the file extension. They are also known as "Personal folders" hence my wanting clarification. According to computer lore, pst stands for "Personal folder STorage" but most people at microsoft deny it. <g> If you go to File, Account Settings the pst files are on the Data files tab. Microsoft is trying to get people to use the term 'data files' instead of 'personal folders', to help reduce confusion.
In Outlook 2010, each email address in your profile may have it's own data file (pst). So you'll have multiple sets of inboxes, calendar folders etc. The screenshot i posted shows 7 pst files, with one expanded to show the folders within it. Each of the 7 has the same basic folders, plus any i added.
If your question is about the things with the colorful icons, those are folders within the pst. They should be in alphanumeric order, save for the first 4.