Our VPS plan can not be converted or upgraded from basic or anvanced hosting. To use our VPS hosting, you will need to place a new order with us from here: https://www.dynadot.com/web_hosting/about.html
Please notice that our VPS is unmanaged and you may need to manage it by yourself. Also if you decide to us our VPS plan, please make sure you backup your website settings on your advanced hosting.