You want to give baby an enema once it stands up to help pass the first poop. It can be extremely difficult and you don't want them straining. First poop is usually passed in 4-6 hours. Anything longer then that, I'd give another enema.
Stand up and nurse within an hour or so.
Mare must pass the placenta/afterbirth within 3 hours. If not, call the vet before infection sets in.