Moving a Box with the Mouse

Copy, Pasted and tested that code. This is what I wanted somewhat.

Could anyone explain abit this to me in detail. This gonna help my learning of Blitz

Alot of symbol :|
If MH And MX => b\x# And MX < (b\x#+b\width) And MY => b\y# And MY < b\y#+b\height Then b\dragged = True

Function updateBoxes()
	MD = MouseDown( 1 )
	MH = MouseHit( 1 )
	MX = MouseX()
	MY = MouseY()
	MXS = MouseXSpeed()
	MYS = MouseYSpeed()
	If MD Then
		For b.box = Each box
			If MH And MX => b\x# And MX < (b\x#+b\width) And MY => b\y# And MY < b\y#+b\height Then b\dragged = True
			If b\dragged Then
				b\x# = b\x# + MXS
				b\y# = b\y# + MYS
			End If
		Next
	Else
		For b.box = Each box
			b\dragged = False
		Next
	End If
End Function