Is my account safe when I create post?

Yes, your password is not stored.

Is my account safe when I use SteemConnect?

Yes, SteemConnect.com is trused service by Steemit Inc. and Busy.org

How do you post my post to blockchain?

This tool is using Steem-js JavaScript library.

I don't know what is power up, witness, vest?

Please read Steemit.com FAQ

I found an error. How can I contact @fbslo?

Please contact me on Steem.chat or Discord - Contact Info

Is this project open source?

Yes - GitHub