Direct answer
Fondant is sugar paste rolled flat and draped over a cake. The skill is in getting the cake surface smooth enough underneath, rolling the fondant even, and lifting it without tears. Most beginners can get a clean one-tier fondant cake on their third attempt.
Buttercream forgives. Fondant does not. That is the first thing to know. You spend more time prepping the cake underneath the fondant than you do on the fondant itself.
Start with a stiff buttercream crumb coat that is chilled hard. The colder the cake, the easier the fondant will lay. Roll the fondant a little thinner than you think: 4 to 5 mm is right. Use cornflour, not flour, to stop it sticking to your rolling surface.
Lift it with the rolling pin, not your hands. Drape it from one side. Smooth it from the middle outwards, working air bubbles down toward the bottom edge. Trim with a pizza wheel, not a knife.
The first one will have cracks. The second will have lumps. The third one will mostly work. By the fifth you will be making decisions about technique, not survival. This is exactly the pacing we teach in the beginner's class: we do not promise you a perfect cake the first time. We promise you understand why it broke when it broke.
Questions on this
What temperature should the fondant be?
Room temperature, slightly warm in your hands. Cold fondant cracks; warm fondant tears.
Can I colour fondant at home?
Yes, with gel colours not liquid. Liquid changes the consistency too much.
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