Here are some steps to decorate a cake for beginners:

1. Bake your cake and let it cool completely.
2. Level the cake by cutting off the top with a serrated knife.
3. Apply a thin layer of frosting on top of the cake to create a "crumb coat." This will help keep crumbs from getting into your final layer of frosting.
4. Chill the cake in the refrigerator for 15-20 minutes.
5. Apply a thicker layer of frosting on top of the crumb coat.
6. Use a bench scraper or spatula to smooth out the frosting.
7. Add any decorations you like, such as sprinkles or fruit.

Here is a more detailed step-by-step tutorial from [Sugar Geek Show](https://sugargeekshow.com/news/how-to-make-a-cake/) that you might find helpful.