That sound brilliant, Phil21.
I run it on a fairly ancient Windows laptop and it's okay. I'm hoping to get a TV and HDMI to it when I get round to tidying up my Zwifting suite - it's a bit of a mess atm. I've tried riding on an iPhone 7 screen before and, while it's okay for just pootling or workouts, it's much too small for racing.
For controlling, I run an AutoHotkey script on the laptop and have a Bluetooth remote button thingy on my handlebars so that I can navigate, activate power-ups, take photos, adjust workout bias etc without having to fiddle with the laptop. There's a good guide
here.
HRM is essential if you're interested in racing - most races won't give you a classified 'zwiftpower' finish if you don't have a monitor. I use a Garmin Dual - connection can be flaky at times.
In spite of the rampant cheating, racing on Zwift is brilliant and brilliantly addictive. There's a separate race classification website called zwiftpower which is a goldmine of data and rankings.
Registering is a bit of a convoluted process, but it's a one-time thing.