SSRS - add to existing report a dropdownlist with parameters

I am enhancing a report in SSRS. This is only my third report so I still have a lot to learn and many questions. I am googling how to get parameters to run the report from a dropdownlist.

This (http://stackoverflow.com/questions/4...in-ssrs-report) is in answer to someone's question who wanted to populate a dropdown instead of a textbox. Sort of like what I want to do, but I am starting with nothing rather than with an existing textbox. Actually, now that I think of it I could start with a textbox, if that would be easier... I will look into that, too. But my problem is that answers to questions posed online assume a certain knowledge which I don't yet have, and below for example when he says "right click the parameter", is this in Visual Studio and if so, where exactly? And if the parameter doesn't exist yet, how do I add it? (If you know of a link that explains all this that would be a big help, so I don't have to keep posting my questions).

Right click the parameter

Select "Available Values" section

Click the "Get values from a query" option

Select the appropriate dataset and fields

I should explain something else before I ask for your help or waste your time. Or at least explain to you that I am terribly confused.

Account Profile Report is a report in a VB6 application that was a Crystal Report but was converted to SSRS. When you click on the icon for this report, it brings up a form with three dropdownlists. After making your selections, you click the Refresh button, and it opens the report as a PDF file. It does this using ReportViewer.exe. The stored procedure it is running in the VB6 code is called pRPT_AccountProfile.

What I am supposed to enhance/fix is when you run this report "directly" from SSRS. I guess they want users to be able to do this without having to run the VB6 application. But it is not working correctly and that is because it does not present the user with the three dropdownlists. So when you run it, the report you see is the last one that the dropdownlist values were set to in the VB6 application. I believe that is because the ddl values are saved in a table called rptSelections. So basically, SSRS never asks you what you want to see, it just runs from prior settings.

So my first question is that in order to have SSRS prompt for parameters, the stored procedure it calls has to have them as inputs and it will automatically prompt? The only parameter pRPT_AccountProfile has is @UserID. And actually (here comes the confusing part) the project in SSRS doesn't even run the stored procedure pRPT_AccountProfile. It runs a bunch of other ones (I will ask the original developer why that is). So do I need to have a stored procedure run that needs these the three parameters set by the dropdownlists, and SSRS will prompt for them? (I am looking at another existing report that prompts for a user ID and a date, and that seems to be what is going on).

Okay, let's forget this whole thing. The original developer just paid me a visit and said I had every right to be confused and said when he converted the report from Crystal his intention was that it would always be run in VB6 and wrote it in such a way that it could not easily be run from SSRS. So I apologize for even getting started on this...