If you've a free account you should be able to setup a simple workflow that sends an automated email to the contact who submitted the form. You need a paid plan to add more actions though. You can personalize the content of the email as needed.
In terms of notifying admin when forms are submitted you can include the email address in the box below when setting up the form or alternatively just setup user noticiations as outlined here.
If you want to do anything more advanced you'll need to consider upgrading to a paid tier (Marketing Hub Starter).