How to properly connect LED strip to Arduino?

Question

Arduino

There is an Arduino Uno R3, an LED strip (single color) about 1m long, an adapter for a 9V, 300mA strip.
Actually the question is how to properly connect the LED strip to the Arduino for simple on / off control. I saw circuits with different transistors, circuits where the Arduino was powered by 12V and power was taken directly from it for the tape, I saw circuits where the tape was powered separately. I tried to collect one, where separately - it did not work out. Apparently I'm missing something. I didn’t dare to assemble one where they connect via Arduino, since there is still no knowledge of how safe it is.
I just received the Arduino yesterday, I started to figure it out. And knowledge in electronics at the school level only.
Please advise a solution, preferably in the form of ready-made diagrams + detailed explanations for them (so that there is still an understanding of what I am doing during the assembly process).

Answer 1

The main thing to remember from school is Ohm's Law and its variants for different types of circuits.
What does it say on the ribbon power adapter? It lists the maximum current and voltage this adapter will put out to cover the power needs of the tape.
Based on this data and a series of articles on easyelectronics.ru on the topic "Controlling a powerful DC load", you can select a control element (relay or transistor) and its switching circuit.

Answer 2

Lay out your circuit, let's figure out where you screwed up ...
... you feed the fool from the power source of the LEDs, and the tapes themselves through the transistor in the key mode controlled from the fool ...
The fool has 5 volts on his feet, and you should not hang more than 100 milliamps per leg , yes, it won’t work out for you, because the LEDs in the tape are in series with a resistor ...