Does the follow-up emails get sent as a reply to the original one or all they all sent as new emails?
If the subject of follow up email sequences starts with “Re:”, “RE:’, “FW”, “FWD” (looks like a reply or forward) then follow-up emails are always sent as a reply (i.e., the previous email for the sequence will be quoted).

Can I schedule a campaign to be sent out later at a certain time?
Yes – you can.

Am I able to send bulk emails? Or are these sent individually?
Gmail Auto Follow Up supports both auto follow-up on individual emails and auto follow-up campaigns (bulk emails):
How to create a campaign with automatic follow-ups
How to set up auto follow up on individual emails