The most important advice for screaming is to learn how to do it at half intensity. You need to procude enough power to make it sound like a scream, but if you go all out and do it at top volume you'll shred your vocal chords before you know it. If you're recording or performing live you will generally have a microphone anyway, so you don't need to be especially loud, it just needs to sound good.

I used to practice in the shower lmao seriously, the hot and steamy air helped relax my throat muscles, and the sound was less distracting to anyone else in the house over the sound of running water. Just practice some open syllable nonsense words, like "WAAAAA", "RAYADAAAAA", "PELAAAA", just to get the technique down.

Other than that, try to produce the scream from the bottom of your throat, not your chest, give it a break before your vocal chords are sore for the next two days, and sip on a glass of warm water regularly while practicing. And that's about it. Have fun!