Electronic components can be divided into two groups: discrete electronic components and integrated circuits.
These are miniature circuits etched onto a piece of silicon, often called a chip. These chips are fitted inside a protective plastic package and are manufactured in large quantities.
The circuits inside the package are arranged in different configurations depending upon the type of chip and its function. The most common type of configuration is called the dual-in-line or DIL package, which has two rows of connecting 'legs', one on each side.
You don't need to understand how the circuit inside a silicon chip works. It's best to think of ICs simply in terms of their function: eg as timers, counters,logic gates or operational amplifiers.
Normally they are one of the process blocks in an electronic system, as in the image here:
When using ICs you need to know:
A circuit diagram that includes one or more ICs should show the pin numbers and how the pins are connected to the rest of the circuit.