How to introduce a schedule?

Howdy!

So my LO is 4 months and I’d to know what the best way to introduce a real schedule to her is.

Do I just jump in on it or introduce it gradually?

What are some of anyone’s success with one or the other?

What were some cons to one or the other?

Or is it all based off of what works for the kid?

Any and all helpful hints and advice is very welcome!

Thank you!