First enable "Microsoft Excel 9.0 Object Library" and "Excel ctl Type Library" in Project -> Referances
Here is some very simple code that will allow you to open an excel application, set and read cell values and close the application. Put it in a module and try calling the functions. This should get you started
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Dim x1 As Excel.Application
Dim x1Wb As Excel.Workbook
Dim x1Sh As Excel.Worksheet
Sub OpenExcelFile()
Dim filename As String
Set x1 = CreateObject("Excel.application"

filename = x1.GetOpenFilename
Set x1Wb = x1.Workbooks.Open(filename)
Set x1Sh = x1.Worksheets("Sheet1"

x1.Visible = True
End Sub
Sub CloseWorkbook(SaveIt As Boolean)
x1.ActiveWorkbook.Close savechanges:=SaveIt
End Sub
Sub CloseExcel()
x1.Quit
End Sub
Sub CloseForm()
Call CloseExcel
ExcelForm.Hide
End Sub
Sub SetCellValue(cell As String, value As Variant)
x1Sh.Range(cell).value = value
End Sub
Sub MakeCellActive(cell As String)
x1Sh.Range(cell).Select
End Sub
Function ReadActiveCell() As Variant
ReadActiveCell = x1.ActiveCell.value
End Function
Sub SetCellActiveRelative(RowOffset As Integer, ColOffset As Integer)
x1.ActiveCell.Offset(RowOffset, ColOffset).Select
End Sub