Before treading into topics of LGBTQIA+ interest, it is worth developing a basic knowledge of "the acronym". Very basically, it can be broken down into the following categories:
Lesbian: somebody who identifies as a woman who is attracted in some way to other people who identify as women. Like many letters in the acronym, this is not an exclusive term, and is used by some nonbinary people, transgender people, and cisgender people to self-identify.
Gay: an umbrella term that is most often used to indicate a man who is attracted in some way to other people who identify as men. However, "gay" is commonly used by many queer people, whether they identify as men or not.
Bisexual: a term used by people who are attracted in some way to people of the same gender and also of different genders. Traditionally, this has been understood as a person who is attracted to both men and women, but over time, it has come to indicate somebody who is attracted to individuals across the gender spectrum, including nonbinary, intersex, and transgender people at times.
Transgender: an umbrella term used by people who do not identify with the gender they were assigned at birth. Some transgender people identify as transmasculine or transfeminine and alter their gender expression to match their felt gender identity. Other transgender people identify as nonbinary or agender, among a whole host of possible gender identities.
Queer: a term used by LGBTQ+ people who prefer not to associate their identities with any one letter. Queer is also an umbrella term for LGBTQ+ people who identify with multiple letters in the acronym or perhaps none at all.
Intersex: a term used by individuals born with diverse sex development. Not all persons with intersex traits identify as intersex.
Asexual: an umbrella term used by individuals who do not feel sexual attraction (asexual) or romantic attraction (aromantic). Some asexual people identify with other letters or none at all.
And there you have it! The acronym is always changing, and this is a good thing. The more people are able to safely and healthily live their lives in the way that works best for them, the better off we become. For more terms and definitions related to queer identity, check out this resource from the HRC: https://www.hrc.org/resources/glossary-of-terms.