Using desktop phone and call forwarding in Europe

I am spending 4 weeks in the UK and will be working remotely while I'm there. Am I able to take my Ring Central desktop phone with me and plug it into my wifi, and use it through my computer? Will this allow phone calls to come in from the US and allow me to call the US as if i was still in the States, or will there be extra charges associated? On that same note, if this is something I can do, would I be able to still use the call forwarding feature to send phone calls to my mobile phone while in the UK? I am trying to avoid any extra charges and I can't find detailed information about a situation like this.