Okay. I’ll help you out a bit here because I feel bad for your lack of knowledge on the subject.
Transgender is when you change your sex.
Homosexual is when you are attracted to the same sex.
Bisexual is when you are attracted to both male and female people.
There are a ton more sexualities and gender identites so I suggest you go look some more if you are interested. I only listed three generalizations to give you an idea of it.
Édit; oops I forgot to add straight. If you are straight you like females if you are male and males if you are female.