Name the Worksheet it's filename - excel

Question

I have been searching for the answer to this question and have found some helpful hints but can't make it work within this code.
I'm copying three tabs and the workbook's name is in Cover!R11 but the other two tabs from that file need the filename as well with an extension (i.e. Filename, Cover, Filename Summary, Filename Estimate). If I reference the cell with the filename when I'm on the second sheet, how can I reference the previous sheet? That's why I thought it easier to use the Filename instead. I tried using: Sheets(SheetName1).Name = FilePath but I can't figure out how to trim it within this code. Can you help?
Here's the code:
Sub CopySheets()
Dim DialogBox As FileDialog
Dim FilePath As String
Dim SheetName As String
Set DialogBox = Application.FileDialog(msoFileDialogFilePicker)
DialogBox.Title = "Select Estimates to copy " & FileType
DialogBox.AllowMultiSelect = True
DialogBox.Filters.Clear
DialogBox.Show
If DialogBox.SelectedItems.Count = 1 Then
FilePath = DialogBox.SelectedItems(1)
End If
For i = 1 To DialogBox.SelectedItems.Count
Application.ScreenUpdating = False
Application.DisplayAlerts = False
FilePath = DialogBox.SelectedItems(i)
SheetName1 = "Cover"
SheetName2 = "Summary"
SheetName3 = "Estimate and Schedule "
Set closedBook = Workbooks.Open(FilePath)
closedBook.Sheets(SheetName1).Copy
After:=ThisWorkbook.Worksheets(ThisWorkbook.Worksheets.Count)
Range("B2:Z97").Select
Selection.Copy
Application.CutCopyMode = False
ActiveSheet.Unprotect Password:="zxc"
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
'The file name I want to use is in this field, but I can't reference it for the other tabs.
Sheets(SheetName1).Name = Range("R11")
closedBook.Sheets(SheetName2).Copy
After:=ThisWorkbook.Worksheets(ThisWorkbook.Worksheets.Count)
Range("B5:K39").Select
Selection.Copy
Application.CutCopyMode = False
ActiveSheet.Unprotect Password:="zxc"
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("D1").Select
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Application.CutCopyMode = False
'This line here didn't work to pull the previous sheet's value in R11
'Sheets(SheetName2).Name = prevname.Range("R11") & "Summary"
closedBook.Sheets(SheetName3).Copy
After:=ThisWorkbook.Worksheets(ThisWorkbook.Worksheets.Count)
Range("A3:M70").Select
Selection.Copy
Application.CutCopyMode = False
ActiveSheet.Unprotect Password:="zxc"
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
closedBook.Close SaveChanges:=False
Next i
Application.CutCopyMode = False
Application.ScreenUpdating = True
Application.DisplayAlerts = True
End Sub

Answer 1

If you want to use the value from 'Cover'!R11 later in the code store it in a variable.
'The file name I want to use is in this field, but I can't reference it for the other tabs.
Dim strFilename As String
' other code
strFilename = Sheets("Cover").Range("R11").Value
Sheets(SheetName1).Name = strFilename
' more code
Sheets(SheetName2).Name = strFilename & " Summary"
' even more code
Sheets(SheetName2).Name = strFilename & " Estimate"