Normally on StackExchange sites, answers are supposed to be comprehensive and not merely link to other resources. However, you're asking two pretty basic, but very broad, questions here.
- How do I configure the CentOS firewall?
- How do I configure vsftpd on CentOS?
I can't write an answer which gives you everything you need to know about those, but I strongly suggest you find some good documentation and have a thorough read. I don't use CentOS, so I have no direct experience of how it does things by default.
You may find these sources useful,
I strongly encourage you to read the CentOS site, and read about the vsftpd service, and understand how to configure it, because even if someone on this site fixes your current issue, you'll run into another one and be back to ask about that. You're not asking about a fault or an issue, you're asking for basic information on how to complete the setup, and the best way to achieve that is to read the documentation.
By all means, if you follow the documentation and something doesn't work, come back and formulate a question about that specific issue, but I urge you to not simply install services and hope they work without understanding how to configure them.