When I hit the Plus sign and add an item to the estimate the seach whindwow comes up and I selet "your product/Service" and revise it. When I add stuff this way it does not go into the data base to select from later. When I go the the "Window" menu at the top and add a product this was it goes onto the list for future use. Can I go back and add product I have entered to the data base list?

When you add items using the plus sign it adds them to the current estimate. Now there are two options, Custom and Product/Service. The Product/Service item allows you to add a specific item you have already entered into your database using the Window -> Products and Services menu option.

When you use the custom option you are creating an item that will only be used this one time. It will not be saved into the database.

So whenever you have a product or service that you reuse often you should use the Window -> Products and Services menu option and add it to the database.