Sleep training?

Anyone sleep training their 16 month old? If so how would I even go about that? (Stupid question I know).

My son used to be a fairly good sleeper. We put him down at 7 and he would sleep until 5:30-6, but since the end of February beginning of March he’s been waking up way sooner, like 2:30-4:30. The only way to get him to calm down and go back to sleep is a bottle.. I’ve tried rocking him, etc. and it only makes it worse. Plus it’s not helping matters that I want to take away the bottle soon too.. 😬 It’s the only time he ever has a bottle.

Advice would be amazing!