There are many ways to make royal icing, and there’s even a link here on CakeJournal by Louise on how to make it, but I cannot suggest you use real egg white as to the risk of Salmonella. Therefore I recommend using 3 tablespoons of dried egg albumen/or Merriwhite (meringue powder works too) and 500grams of icing sugar. I usually just stir the egg white into the icing sugar, then add a little water an eggcup at a time and mix in a mixer with the beater attachment on and mix for about 7 minutes, scraping down the sides half way through. Adding too much water will ruin your icing so, always make it on the stiffer side first. Royal icing goes hard quickly so keep it tightly wrapped in cling film between using it. Any left over can be kept in the fridge for up to two weeks if air tight. Hope that helps. Gillian x