I’ve used a kit like this for a few years now for installing ILs, Happs, and wico leaf joysticks.
↓ I second what u/latestagepersonhood said. If you don't want to cut into the stock harness, you can buy this connector Amazon Link that'll plug into the stock headlight plug and connect the Black for ground to led bar and choose either red or blue to the positive. Most times the Blue is "hi beam" so the led bar will only turn on when you switch the "hi beam, and vice versa with the red "lo beam".
Edit: Since your new to wiring I also suggest getting this wiring crimp set Amazon link. It has way more than enough plugs and will come in handy in future projects. It has sleeves to prevent wires touching and shorting out and is way better than those regular crimp style ones because it squeezes onto insulated part of the wire as well and prevents it from being pulled out.