If you haven't done so already, make sure that wear pads are fully fastened to the sub chassis and that pivot bush and bolt are securely attached.
Fit the tilt bolt and nylock nut and securely tighten.
Grease and fit the bearings, hubs and wheels and torque the stub nuts up as per the settings below.
Torque Settings for wheel nuts are
7/16" UNF 110Nm or 80 Ftlbs
1/2" UNF 125Nm or 90 Ftlbs
Fit amber reflectors to the side of the drawbar brace and fit safety chains and shackles to the front of the drawbar.
Mount the coupling using good quality bolts and ensure they are torqued as per the suppliers recommendation.
Double check that all lights and brakes (if fitted) are working correctly.
Wheel straps and vehicle restraining safety chains need to be sourced to secure the towed vehicle to the trailer. Contact your local webbing or rigging suppliers and they will custom make wheel straps and chains to suit.
Put a dab of grease on the towball and hook the trailer up to your tow vehicle and double check that all the lights are working.
Grab a new vehicle registration form from your local DMV or vehicle registration centre, fill it out and license your new trailer. Attach your new license plate to your trailer and book the trailer in for a certificate of fitness if required in your state.
Once the trailer is licensed and certified it is ready for loading!
After around 100 miles or so, go around all the coupling bolts, pivot bolt, wheel nuts and guard strap screws and check all are in position and tight. Don't forget to do regular 3 monthly maintenance on your trailer to keep it in good working order!
Good luck and happy trailering!