Breadboard is an important tool for electronic circuits prototyping, it gives you possibility to easily interconnect and test components you need before any other superior step like translating everything directly on a copper clad circuit/laminate board; and it's reusable for a long time.
Arduino is one of the most famous microcontroller board.
Trying to explain what exactly it is shows multiple difficulties that progressively fade away with practice.
Maybe one feature could intrigue above all others: programming language is a high level one!
One classical example to take confidence in electronic circuits is related to charging/discharging capacitors (symbol: C).
These components are able to catch electrical charges and to keep them for a long time; theoretically for an infinite one, but this is impossible, first of all because of Joule effect (heat dissipation to the ambient with slow progressive energy loosing).