My interests & about me
About me & description
You can specify everything that interests you and what you would like to share with other users in your profile under "Details". The more detail you go into when describing yourself, the more others will be keen to get to know you.
In your profile, you can change your search settings (gender, age) for the Match game and the profiles in your environment under "Details".
You can also change you search settings in your profile settings.
It is not possible to search for users by username.