What do i need

So ive got a lemond trainer and i was going to start riding on zwift, i have a garmin 510 how do i go about using zwift i have a cadence and speed sensor and heart rate sensors, do i need to buy ant+ usb if so, how do i go about setting everything up so i can ride, sorry im abit stupid aha

You don’t need the Garmin 510, but you do need a USB stick - you plug the stick into the PC and your sensors talk to it to send cadence, speed, hr etc.  I don’t know what a lemond trainer is but check on the zwift homepage to see if its supported or not. 

You need a power meter with the Lemond.

Or the optional LeMond Wattbox that broadcasts power.