VBA问题不理解求解释

请问有人给我细致地解释一下这部分代码中“自动跳转至目标工作表进行筛选”那里每一行的含义吗？VBA理解题
Private Sub Worksheet_SelectionChange(ByVal Target As Range)

Dim Rng, oRng As Range      ' 定义变量Rng、oRng为单元格

Set Rng = Range("B2:B18")   ' 设定Rng为可操作区域单元格
Set oRng = Selection        ' 设定oRng为选中单元格

'如果所选单元格在可操作区域外，退出本次运行
If Application.Intersect(oRng, Rng) Is Nothing Then Exit Sub

Application.ScreenUpdating = False

' 多选则退出，单选设置筛选值
If Selection.Count > 1 Then Exit Sub Else AimValue = Selection.Value

' 自动跳转至目标工作表进行筛选
With Sheets("权限分配表")

    If .FilterMode = True Then .ShowAllData
    .Range("A1").AutoFilter Field:=1, Criteria1:=AimValue, _
     Operator:=xlAnd
    .Activate

End With

Application.ScreenUpdating = True

End Sub