Setting a Script to Script Tool in Toolboxes

Have a question. So to put my script in a script tool, I need to add Parameter information into the code. When you create a script tool you have to set its parameters from your code to have it work. And I don't think my code has parameters set because it does what I ask it to do programmatically not systematically. Please look at my code below and let me know if I'm right.

import arcpy, os
folderPath = r"C:\2 - GEO-DATA PROCESSING SUPPORT\Permanent Site Maps\2_District MXDs"
for filename in os.listdir(folderPath):
fullpath = os.path.join(folderPath, filename)
if os.path.isfile(fullpath):
basename, extension = os.path.splitext(fullpath)
if extension.lower() == ".mxd":
mxd = arcpy.mapping.MapDocument(fullpath)
pdfPath = r"K:\PRODUCTS\Maps\Printable Maps\Test Permanent Site Maps"
arcpy.mapping.ExportToPDF(mxd, pdfPath + os.sep + basename.split("\\")[-1] + '.pdf')