Is there a template I start from?
Not a design template. There is a fixed structure a webinar page needs, and you fill it: the chapters, the speaker section, the form, the seat line. Nothing is rearranged by hand, which is why the finished invitation always works on the first send.
Does the maker create the meeting as well?
No, and that is deliberate. You make the session wherever you make sessions, paste the join address into the page, and type the platform's name. Each registrant receives that address privately rather than from a public banner.
Can it send the invitation to my contacts?
It cannot, and there is no contact import. You publish, copy the address and send it yourself. The maker holds the page and the register, not your audience, which keeps the list of who you meant to invite in your hands.
What does this do that a designed card does not?
It answers back. A card tells people the date; this page collects names, enforces the cap, issues a private way in, and remembers who attended. For a session rather than a dinner, that register is the whole point.
Can I make one invitation for a series?
One page is one session. If you run four dates, build four invitations with four addresses and four lists, because keeping them apart is the only way the numbers mean anything when you look at them later.