Royalties Agreement/Contract

[Brigg]

I have an unusual dilema (to me) in that I have to produce an agreement/ contract for royalties to be paid on sales and hiring of Electro Fusion Welding Machines.

Nominated company will:

stock the product and will sell a branded 'Terrain' machine;

will pay a royalty of 5% for every machine sold with the 'Terrain' brand; and

will also hire stock and attract the same royalty of 5%.

I need advice on how to write this into a meaningful agreement?

All advice gratefully received.

Brigg