See: GetParameterAsText—ArcPy Functions | ArcGIS Desktop
I still find this confusing. Would I set my current workspace as this?: arcpy.env.workspace = arcpy.GetParameterAsText(0)
Probably I'm confused what you're looking for. Are you making a tool that takes a parameter, entered by the user, and sets the workspace environment? If so, then yes, arcpy.env.workspace = arcpy.GetParameterAsText(0) would make the workspace equal to the value entered in the first parameter slot. If not, what exactly are you trying to do?
I'm with Darren on the confused bit... but I presume that this is related to
If one of the tool parameters is based on user input defined using the GetParameterAsText() function, is it possible to use F5 to run the script successfully?
And Mapping Charting is probably not the place to get many responses dealing with toolboxes and/or code
Python would be best
Retrieving data ...