Why i can't using the I, O ??

[미뤠도]

why i can't using the Shortcut I, O ?

it's very hard to moving edge of layer only Ctrl + rudder..

Please give to me solution..

[Dave_LaRonde]

Did you highlight the layer in the composition timeline first?

[미뤠도]

Sorry,  i cant understand your means.. What's the highlight? 

i'm not very well English... Thank you to comment

[Roland Kahlenberg -]

This Q has been asked and answered -

https://community.adobe.com/t5/after-effects/go-to-layer-in-out-shortcut-keys-i-o-not-working-for-me...