Matter is made up of particles called molecules. They in turn consist of one or more atoms linked to one another. In a pure substances all the molecules are identical. When multiple substances are mixed the molecules are mixed. (Often it is also said that matter is made up of atoms.)
Matter also occupies some space (physical property of size or volume) and has some weight. Matter also has other physical properties like appearance etc.
There is also supposed to be anti-matter that is supposed to consist of anti-particles like matter consists of particles. The mass is same as that of a particle but electric charge is opposite. When antimatter meets matter, they annihilate and produce energy E = m c².
Also, there is supposed to be dark matter. It does not emit or reflect light or other radiation, Hence we can not see it directly. But we feel the presence of it by its influence (gravitational) on other nearby objects.
Our Matter exists in four forms (states or phases) in general for all substances.
Solids in general have a rigid shape. They do not flow like liquids on a surface. We can taste them, see them, touch them and lift them with hands. They are harder than liquids and gases.
The form not having a shape of its own and takes the shape of the container. Liquid flows over a surface. Liquid occupies only as much as its volume. We can feel their touch, see them and taste them. Liquids are softer than solids.
The form in which it does not have a shape of its own. It spreads to occupy the whole space available to it. The molecules in gas have more kinetic energy than in solid and liquid phases. Often we can not see the gases with our eyes or cannot feel their touch. We cannot taste them too. We cannot hold or lift gases with hands.
When gases are ionized - parts of the molecules have electric charges on them, then gases also conduct electricity like solids. In our solar system the stars are in this state.
When we say made up of particles X - it means - If we repeat particles X we get the matter. We do not say sub-atomic particles make up matter, because if u repeat them, you do not get the matter.
Atoms alone do not make up matter as there are specific bonds between atoms in a molecule. Those bonds are missing when you take atoms as the repeating structures. In some substances a molecule consists of only one atom.