Simple: Watch for signs at YVR that have a small US flag on them when you leave the arrival gate and head towards the main terminal. Follow these (a corridor to the right) to connect airside to the US customs preclearance area. Do not worry about you checked bag(s) as you will ultimately come out in a area after passport control (US) where these can be collected. From there, you will join the YVR-originating passengers where you'll put your bags back onto the belt and go through security again.

Your flight to YVR is considered Domestic, and the one to Hawaii is Transborder. (If you were on the YVR-HNL flight that continues on to SYD, you'd go to the International wing, but such is not the case with the YVR-HNL-YVR flights.