I know almost nothing about visual basic, and my supervisor asked me to add
some things into the code of a spreadsheet. I know what the code is supposed
to do, but I honestly don't know if I'm doing it right. Can someone tell me
what exactly this is doing??

Sub data()
Application.ScreenUpdating = False
For Each sht In ActiveWorkbook.Sheets
sht.Activate
ActiveSheet.unprotect
Next
Worksheets("Sheet").Visible = True
Worksheets("Data").Visible = True
Worksheets("Data").Activate
Columns("A:B").Hidden = False
region = Worksheets("Sheet").Range("Region").Value
Cells(3, 3).Select
cellcount = Range(Selection, Selection.End(xlDown)).Count
umis = 0
umiu = 0
umip = 0
mcpls = 0
mcplu = 0
mcplp = 0
gvfpls = 0
gvfplu = 0
gvfplp = 0
mshs = 0
mshu = 0
mshp = 0
bdchs = 0
bdchu = 0
bdchp = 0

These letter groups represent product lines that are being pulled from one
sheet and grouped together and placed in another sheet. I have to add another
group, but can I just add it into the code because how will excel know what
it is referencing too?