They are female and they're attracted to other females? It's a pretty simple concept really.
a lesbian and another lesbian kissing
Yes. Lesbians wear t-shirts that say "I'm A Lesbian" to show that they are lesbians. All the time. If a woman is not wearing this shirt, she's not a lesbian.
You don't become a lesbian. You are born a lesbian.
Lesbian
It's a lesbian travel agent. So it's for lesbians. You probably wouldn't have to prove you were a lesbian, but why would you go if you weren't?
Lesbians are already women.
Yes. Part of being a lesbian is liking to touch, lick, kiss other lesbians. If you did not do so then it would be assumed you are not a lesbian.
No. Being a lesbian is not a sin, nor is thinking about being a lesbian (or lesbians in general).
If your girlfriend was a lesbian she wouldn't be with you. Bisexuals date both and Lesbians date chicks.
There is no official status for lesbians. If you are a lesbian, you already know it, deep within yourself.
Lesbians can work in every job they want
Yes, all monkeys are lesbians. Including you.