use checkbox to copy, paste and delete data

hi. here is my problem.

I have 3 worksheets. In sheet1, there will be a list items for Bill. Sheet2 has 2 pictures of building and checkboxes beside them. Sheet3 has list of items needed for buildings stated in sheet2.

What i want to do is, when I check the checkbox in sheet2, it will copy data in sheet3 according to the building name and paste it in sheet1. And when I unchecked the checkbox, it will delete the data that i copied in sheet 1.

I asked somone from other website to help me, and he did managed to make the macro for copying data, but I don't understand it . I really need help.

This is the macro for checkbox to copy data from sheet 3 and paste it in sheet 1.

Sub CBClick()
    Application.ScreenUpdating = False
    If ActiveSheet.CheckBoxes(Application.Caller).Value = 1 Then
        Range("Bld" & Right(Application.Caller, 1)).Copy
        Sheet1.Range("C60000").End(xlUp).Offset(1, -1).PasteSpecial
        Application.CutCopyMode = False
        End If
      Application.ScreenUpdating = True
End Sub

Can someone explain, how this code works

Range("Bld" & Right(Application.Caller, 1)).Copy

Thanks in advance