Welcome to the board and a great hobby!
You've got a great head start here. If you want to get into this hobby, After doing some reading and exploring as Don suggests, one of the first things you might want to consider is to buy a used Scott's catalog (1A US Specialized) which will be a great source of information and help you identify the issues that you have and what you don't have. You can find a catalog that is a few years old for much less than a new version and it will give all the same identification information for these issues. They are always available on eBay
. Values don't usually change rapidly so it'll give you an idea of "relative" value. I've been collecting since 1972 and I always buy two year old catalogs, use them for a couple years and get another.
Short of buying one, you can get your feet wet by checking them out for free at most public libraries too.
As Don mentioned there are great online resources that you should explore.
The stock book is a great place to keep them. You won't need one right away but there are a number of stamp albums available for sale and very good pages to download and print for free. As you have questions this is a great place to ask them. Other basic tools you might need (if you don't have) are a good magnifying glass and tongs (specialty tweezers for handling stamps).
Conversations about all these items are available on this board and can be found through the search feature.