'To do this close your eyes while going to sleep for the night. Spend about a minute looking at the backs of your eyelids. Over time you should start to instantly recognize, even when groggy and half-awake, that your eyes are closed and that is a signal that you have just woken from a dream.'

How do I look at the back of my eyelid? Just close my eyes and focus on the darkness?
or actually try to look backwards with my eyes closed?

Thanks >.<