"– Who are you? – I am Aino."
Translation:– Kuka sinä olet? – Minä olen Aino.
You don't have to include "minä".
I often intruduce myself as just "Hei! Hanna." with no "I am" or "my name is".
If you want to say "My name is", it's "(minun) nimeni on".
nimi - name
(minun) nimeni - my name
(sinun) nimesi - your name
hänen nimensä - her/his name
(meidän) nimemme - our name
(teidän) nimenne - your name
heidän nimensä - their name
Olen should be enough, because it is the 1st form singularis of "to be" - i am = Minä olen. You can skip "minä" and write just olen. That happens to work für every pronoun except "hän" and "he". There the pronouns HAVE to be written every time... at least in written language ;-)
Is it possible to write only "Olen..." or is it shown as false then? Maybe we just find a lot of easter eggs in this beta version :-)
Whether a name is for men, women, or both just needs to be learnt by heart. There is no ending to set them apart. Of course, some names like Liisa have variants in many other European languages as well and are easier to figure out. If you have the web version of Duo, the Tips for Basics 1has a chart which lists all the first names used in the course and tells you whether those names are male, female, or neutral. If you haven't reached that skill yet or don't use the web version, you can access all the Tips via duome, a site maintained by a Duo fan. :)