The only daft question is the one that you sould have asked - but didn't
Protective coating is available for new caravans from companies such as
Paintseal Direct if you feel like splashing the cash, and forum members who have used this service will be able to tell you more about it.
Otherwise, as John said, the first application of polish and wax is all important.
Give the caravan a wash down using a good quality caravan shampoo such as
Fenwicks , rinse and dry, microfibre towels are good for cleaning and polishing.
The use of a pressure washer is not recommended because the mastic seals (where applicable) can be damaged.
Polish and wax are entirely different things, polish will clean paint surfaces and bring to a shine and wax will seal and protect the shine. Two thin applications of a good quality wax are better than one thick application. Prices of products can vary significantly, so choose products that suit your pocket, are easy to apply and which give good lasting results.
Click Here to see more about polishes and waxes.