Transition to supply cups..

Ca

How did you ladies do it? I’m afraid they’re not getting enough milk out of it so I just go back to the bottles. Twins will be 1 on the 2nd and I see 1 year olds with sippys but mine aren’t. They were also preemies so I’ve never been in a rush to push anything on them. Idk it might be a stupid question but help me please 😭