Exactly as Martin says, you’re not going to get it the first time around, you have to practice and keep at it over and over. The teachers in the videos make it look easy but they’ve been doing this over a decade. The example I like to give is that of an illustrator, he uses pen, paper and his hand to make wonderful illustrations, simple tools that you can use yourself, but if you try laying your pencil down to create what an experience illustrator creates and you’ve never drawn before, you wont be able to do it, even while holding the exact same tools. So start over how many times necessary, that’s how it goes for everyone, practice not only sculpting but grit and perseverance, you will start to get better overtime if you practice, it’s guaranteed.