Character creations is a snap with D&D Beyond. The DM will have sent you a link to the D&D Beyond campaign. Once there, you can use the D&D Beyond character creator to make your own character. It's super handy and walks you through the whole process.
Character Creation House Rules
Nearly all first-party content published by Wizards of the Coast is allowed.
The Aarakocra race is banned. I think having a player character having a natural fly speed at first level is a little too powerful for my taste. If you really want to play as a bird person, the Kenku are a great replacement.
If it interests you, you can talk with your GM about playing with Unearthed Arcana content. This content is produced by Wizards of the Coast for play-testing purposes. Much of the Unearthed Arcana content has actually made it into published books after being modified by play-tester feedback.