people post questions like 'how to do spells' because many people are lazy, they don't want to research it themselves. they want the answers spoon fed to them instead of reading a 2 page article on spells.
at the same time, some people do believe you cast a spell and like in Harry Potter, things will appear. asking 'will a fireball appear' a simple no will answer the question, but like i said about, they could get the same answer if they read an article, or a book, or watched a how to video. sign of our times really, to be a witch, is not to cast spells, but to learn. so much of this path is studying alone, but so many people watch Charmed or something and think you can cast spells by standing over a cauldron and reading a few words. when it doesn't work, instead of researching why, they ask for the answer. they will still learn, but it's that old give a man to fish vs. teach a man to fish thing.