I’m pretty much a beginner with electronics so I hope I’m not asking something stupid or obvious, but can I convert a 5V USB powered LED strip to work on the Arduino pins? And if so, is there anything that I should be weary of or should take into account?
And Arduino I/0 pin can only directly power one or two LEDs.
You'll need a [u]driver circuit[/u]. The example shows a 12V power supply but you need to use a 5V supply for your 5V LED strips.
If you have multiple strips separately-controlled, each strip needs it's own driver.
The power supply should be "exactly" 5V. The power supply and MOSFET should have a current rating (amps) of at-least whatever is required for the LEDs (some safety margin is good.)
Since you have a non-inductive load, your driver doesn't need the diode and you can leave it out.