Switching between two workbooks

I am a newbie trying to sort out some code. The code I cuurently have (below) works, but now I want to add to it and go back to the JnlReg workbook paste some information there from Thisfile and then save and close JnlReg.

Thanks in advance

Private Sub JournalReg_Click()
Dim ThisFile As Workbook
Set ThisFile = ThisWorkbook
Dim Sht As Worksheet
Dim Answer As String
Dim JnlReg As String
 
    For Each Sht In ThisWorkbook.Worksheets
    Sht.Unprotect
    Next Sht
 
    Sheets("Jnl Vouch").Select
 
    If Company.Text = "" Then
    MsgBox "You must enter a Company"
    Exit Sub
    End If
 
    Range("rngCo") = Company.Text
    Range("rngEntry") = EntryDate
    Range("rng_pdate") = PostingDate
 
  
ThisFile.Activate
    ActiveSheet.Calculate
    JnlReg = Range("rngFile_JnlReg").Value
    Workbooks.Open Filename:=JnlReg
 
    Sheet1.Unprotect Password:="P"
    Range("A65536").End(xlUp).Offset(1, 12).Select
 
    Answer = MsgBox("The next JV Ref is " & Selection & ". Do you want to use this JV Ref?", vbYesNo + vbQuestion)
    If Answer = vbNo Then Exit Sub
    If Answer = vbYes Then Selection.Copy
    ThisFile.Activate
    Range("rngJourn_Nos").Select
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
        :=False, Transpose:=False

Thank you, worked a treat