@yukinoh1989 Hi Yukino, the challenge of this exercise is to use only primitives, and only object mode, so no edit mode. Which is pretty damn hard to do, but you’ll learn a lot while doing it and you’ll probably get a lot more creative to get the shapes you want.
The boolean modifier is acceptable (this makes holes in your mesh). Other tools you got to your disposal are grab (translate), rotate, scale, snapping, and the properties panel that you get when you add an object (here you can for example change the segments amount, radius, etc.). There might be more but those are the ones I know of.
Yes, the lattice modifier can change your shapes, but as far as I know that one is not part of this exercise. There are probably many other modifiers that change shape but I’ve never used them, so maybe one of the more experienced people here can tell us?
Of course I’m not Kent he has the final say in this, maybe he’s okay with more modifiers 😎