Welcome @kizzume. So you've done the hard part and got through the labyrinth that is the account creation process. I know you were interested in 3Speak, but if you don't want to pay the 30 something Steem to get started there you can post on plenty of different applications.

Steempeak is the best blogging experience but there is also
Steemit.com
Busy.org

For video sharing there's also https://d.tube/#!

For mobile there's
https://esteem.app/
https://appics.com/ < Still in Beta, but can be used now. Basically Instagram for Steem

Let me know if you have any questions :)