Welcome po to Steemit. Some platforms you may also want to check - dtube and dsound. Dtube for uploading videos, and dsound for audio. You can sig-in to the above sites with your steemit credentials.

https://d.tube
https://dsound.audio

And if you're using Android, you may also want to download Steepshot. It's IG built on top of the STEEM blockchain.

It's a whole new world. Start exploring and find your passion and join communities. :)