Once you’ve finished confirming players interested in your Looking for Group post, it’s time to gather them into a party (unless you’ve scheduled the party for another time).
To gather confirmed players into a party:
Press the Xbox button to open the guide, and then select Parties.
Select the Looking for Group post, then select Gather your party. This automatically starts a party and sends party invites to everyone you’ve confirmed previously. (If you confirm anyone else after you’ve selected Gather your party, they’ll be sent a party invite automatically.)