I recently requested information from Dodge about dolly towing my new car and this is part of what they sent back:
When using a tow dolly, follow this procedure:
Properly secure the dolly to the tow vehicle, following the dolly
Drive the front wheels onto the tow dolly.
Firmly apply the parking brake. Place the transmission in PARK.
Properly secure the front wheels to the dolly, following the dolly
Release the parking brake.
It's pretty basic and general but the biggest take away from it is that you should try and find the manufactures info.
Tie down straps can be purchased at different places, I think Harbor Freight has some, but a lot depends on the design of the dolly.
I take my keys out because the deck the car rides on, on my Master Tow, pivots so the wheels don't turn yours may be different.
2013 Coachman Mirada 29DSSE