You are probably searching for this new phase of matter and whatever you are reading is going through right over your head. In that case this simplified version is for you.
First of all we need to understand what crystal is. When atoms, molecules or ions get together and arranged in particular manner, they form crystal. Crystals are generally symmetric when you look at them, but from certain direction it can be asymmetric. But for crystal to have asymmetric structure it should be in ground state. (Ground state is zero energy state, where atoms or molecules or ions have zero energy, which means no vibration). In such still, without any motion state crystals look asymmetric from certain direction.
This was all about ordinary crystals, but for time crystals its’s different story. Motion occurs in time crystals even in zero energy state or ground state. (Which type of motion?) Time crystals rotate periodically in time breaking time symmetry(so they are asymmetric as ordinary crystals). Conclusion: Both types of crystals are (Space) asymmetric in ground state. Time crystals have additional time asymmetry+ vibration in ground state. This is what makes it different type of matter.
So far two teams have created time crystals. One from university of Maryland and other from Harvard. They have recipe to make time crystals and detailed blueprint to measure properties of it. Other teams from all over the world will try this recipe and check whether our new item tastes the same or not.
Its vibration even in ground state raise one question, can it be used as Perpetual Motion Machine? (PMM is machine which generates energy without consuming anything, literally anything). But, no. Since it do have energy in ground state (where it should not have), we would not be able to extract energy from it( at least not for now).
Though we will not be experiencing such phase of matter in day to day life, like we do experience solid, liquid and gas. But that does not mean we should not know about it. In schools, they mostly teach about first three phase only. Students and sometimes even teachers don’t know that we have total six phase of matter now. Plasma, bose-einstein condensate and time crystal are next three. I hope you understand time crystal now. Share with people around you so they at least know about total phases of matter.