If you are unfamiliar with the complexities of identity, expression, attraction, and sex, the best place to learn about them is from the Genderbread Person. You can find more information on Wikipedia: Gender Identity.

The Genderbread Person v3.3 by "it's pronounced metro sexual .com"
An infographic relating the aspects of gender.

Three good glossaries of LGBTQIA+ terminology:

NPR: A Guide to Gender Identity Terms
HRC: Sexual Orientation and Gender Identity Terminology and Definitions
CDI: Equity and Inclusion Vocabulary

Resources for LGBTQIA+ folks

Local/Campus: CDI Resources Page
National: HRC Resources Page

Resources for workplace inclusion

The Muse: 11 Simple Ways You Can Make Your Workplace More LGBTQ Inclusive
NPR: 4 Ways to Make Your Workplace Equitable for Trans People
The Muse: A Guide to Using Pronouns and Other Gender-Inclusive Language in the Office
The Muse: What I’ve Learned About Coming Out as Bisexual at Work—After Doing It at 11 Jobs

Three good glossaries of LGBTQIA+ terminology:

Resources for LGBTQIA+ folks

Resources for workplace inclusion

More reading on LGBTQIA+ issues and culture