Matter reflects light, which is why we can most often seen it. Matter is composed of elements such as Hydrogen, oxygen, carbon or else gold. that are called Atoms. There are hundreds of fundamental elements and these can be observed on earth in various states: solid, liauids or gas and even other intermediate states such as plasma or moisture.
Each element has its own behavior regarding its environment and its neighbouring Atoms, and physics and chemistry are the sciences that enable to understand their behavior. Thus human have tried to make use of materials depending on their advantages and drawbacks their will have for a given application. For example, paper has been used for 500 years because it is light, easy to produce, and solid and durable enough to transmit and record ithe nformation in books or newspapers. Silicium is widely used to produce micro-electronic components such as transistors because it has specific electrical properties, but also for other reaeasons sch as because it is widely available on earth and can easilly be transformed to very very very tiny communication devices.
Humans have developped technologies and know-how to produce matter based on a single element (e.g; distilled water) or alloys of complimentary elements (e.g; steel is a mix of Iron and Carbon, which make a very solid material compared to iron or carbon) or other types of combination (e.g; electronic devices that are made of various functionnal parts, layers and components)
Humans constantly develop new comboinations of materials so as to create better solutions in terms of efficiency, durability or production costs so as to develop more sustainable products. Thus, If you believe for instance taht paper is an insulator and does not conduct the electricity, you will be righ most of the case but you will also learn here that an alloys of paper and conductive elements can get conductive enough to be used in electronics.
Is that all I need to know?
Nope! You should also check the basics about atoms which will give you the key to understand what is electronics and an electric charge, and why some materials are conductors and others are insulator when submitted to an electrical field.