two questions referencing a cell in a macro for folder and running a macro on one sheet

Hi there! I have 2 questions, but first I will input the code:

Sub automkdir()

Sheets("X").Select
Dim xdir As String
    Dim fso
    Dim lstrow As Long
    Dim i As Long
    Set fso = CreateObject("Scripting.FileSystemObject")
    lstrow = ActiveSheet.Cells(ActiveSheet.Rows.Count, "H").End(xlUp).Row
    Application.ScreenUpdating = False
    For i = 2 To lstrow
        'path to create folders
        xdir = "C:\Users\blue\Documents\" & Range("H" & i).Value & Left(Range("G" & i).Value, 1)
        If Not fso.FolderExists(xdir) Then
            fso.CreateFolder (xdir)
        End If
    Next
    Application.ScreenUpdating = True
       
'    Application.OnTime Now + TimeValue("00:01:00"), "automkdir"

End Sub

So this formula works great except for 2 things - It runs on every workbook, I want to limit it just to the workbook and sheet I'm in. I also don't even need it to be running in the foreground and would prefer it just run silently in the background no matter what others worksheets or workbooks I am in, as long as this one is open.

The other problem I have is instead of C:\Users\blue\Documents" I want it to read blue as a variable that I input on lets say Sheet "Y". So if sheet Y has "blue" in Cell A1, and I change is to "red", the macro will look for C:\Users\red\Documents" instead.

Thank you for your help!