How do you trim layers?

[ImASecretTwigletNibbler]

DS's hair needs cutting. He has one of those surfer-dude styles with lots of layers - is there any way of doing this myself?! I've found hundreds of YouTube tutorials on how to cut layers into hair but I can't find naything about how to trim hair which is already layered.

Anybody?

My ds has very thick choppy layers like Liam Gallagher from Oasis. I trim by taking a section lengthways from the top of his head and cutting across ifyswim.

For the back of his head, I lift a section of hair from the nape of his neck in an upward direction. Then I trim at an angle pointing the scissors downwards.

Trimming layers is a bit similar to cutting them in, just make sure that the length is similar all over & there aren't any bits sticking out.

Tht's what my DS's hair is like too! I think what I'm struggling with is how to section the layers in the first place. If I pick up a bit of hair then it's got bit of hair from several layers in....

It's a job for a hairdresser.