It's important to remember and acknowledge intersectionality, as everyone has multiple identities, and experience discrimination and privilege in different ways.
The acronym LGBTQIA+ stands for “lesbian, gay, bisexual, transgender/Takatāpui, queer, intersex, asexual/aromatic/agender and other gender and sexual minorities.” Terms such as rainbow and queer are also sometimes used as blanket terms for all these sexual minorities. You don’t need to understand all these terms, but to be respectful and listen.