Need to Host without sending an email invite; only using passcode. I will emessage to all invitees.

Mom's 104th birthday is today.  We are to celebrate her birthday with relatives across the country at 2pmEST.  That is 2.5 hours from now.  I will host the zoom meeting.  I will contact all intended participants via emessaging from my iphone; all information sent to them will be via this means.  I will be hosting via my laptop.  Once I start the meeting, what information do I need to convey to them and where do I find it; again, no emailing is possible.