Can someone help me to explain this procedue?

DoEvents
TmpDir = Dir(DrivePath, vbDirectory)

Do While TmpDir <> ""

If TmpDir <> "." And TmpDir <> ".." Then

If (GetAttr(DrivePath & TmpDir) And vbDirectory) = vbDirectory Then
XDir(DirCount) = DrivePath & TmpDir & "\"
DirCount = DirCount + 1
ReDim Preserve XDir(DirCount) As String
End If
End If
TmpDir = Dir
Loop
'Searches for the files given by extensi
' on Ext
FFound = Dir(DrivePath & Ext)


Do Until FFound = ""
DrivePath
FFound = Dir
Loop
For X = 0 To (UBound(XDir) - 1)
FilesSearch XDir(X), Ext
Next X