You're very welcome. I hope you have a great hatch of healthy chicks After the first pip it can still take as long as 24 hours, just depends on the chick.
Sorry for answering late, but most recommend leaving it closed as much as possible to preserve the humidity. If you have no issue getting the humidity back up easily then it's ok to open it briefly. Has you chick started zipping the shell yet?
They will rest for a bit sometimes so you may not hear peeping for a couple hours occasionally. a trick some use is putting the sound of peeping chicks near them. It encourages them to hatch faster.