when do layout group component place their element?

I'm Implementing player's toolbar slots, and they are aligned by horizontal layout group component. ![alt text][1] and I'm trying to place an indicator where the current toolbar slot is, but when I place the indicator in awake or start, slots are not stating aligned. ![alt text][2] in my think, it's slow to place slots than awake or start function. is it correct what I think? and how can I fix this issue? (I fixed this issue by calling Invoke function but that's not intuitive.) [1]: /storage/temp/184584-제목-없음.png [2]: /storage/temp/184585-제목-없음.png