I think you may be a troll and this is likely a bait. If you wanted to go with a reliable and low-cost method not minding the pain, there's plenty of resources on that. This site is targeted by trolls, and you may be one of them.
All the tips you may get here would be from people who are alive, therefore either unsuccessful with that (or any other) method or never tried it. This limits the usefulness of those tips.
If you honestly consider this method, not just trying to be edgy, I would recommend you to rather seek help. This site is pro-choice, which means that it supports the right to live or to die in any adult "of a sound mind". I wouldn't be sure about the soundness of mind of a person who ignores tons of resources on reliable methods, and opts for a method from a horror movie. So I wouldn't feel comfortable giving any tips to a person who refuses to read the stuff that is in front of them anyway. I think we shouldn't gatekeep for "good enough reasons", but we shouldn't give tips to people who don't read anyway.
You should at the very least study a bit of anatomy/see some videos and locate your arteries to stab directly there. The carotid is the best one because even if you don't hit it but hit the jugular vein instead you still die.
You'll also want a very sharp blade that can pierce through your tissues, a electric saw would probably be ideal tbh Also be warned that if you hit fascia (connective tissue between fat and muscle) it will hurt like hell and it is very likely that your SI kicks in if that happens.
Anyway this method is messy and not for everyone, if you are not accustomed to self harm then I'd suggest hanging or another method instead.
If this person doesn't read the resources on the forum anyway, why would they study videos? It honestly looks like trolling, and I don't believe that giving tips to people who either are trolls or lack some basic literacy could help anyone. It gives the site a bad name of promoting, encouraging and whatever else :/