Hi again @guykimchi
OK, if you're talking about he main pattern that's going on during the all track ( and that you can clearly hear in isolation at 3:30 in the vid ) then it's not really a melody, it's a kind of plucked Bass Synth with a very short attack and probably a lot of distortion/saturation and probably opening the cutoff of the filter with some automation. It's also layered and stack on the top of a bass following the same midi pattern, so it's not just one sound.
Many synth plugins will allow you to reproduce those sounds, but if you're just starting it might not be obvious or that easy just now. It's good to learn the fundamentals of synthesis and how you can make your own sounds with those plugins or modify existing presets and use the right parameters to tweak with automation in order to bring the sound to life during a track progression.
Have you consider to try a Sonic Academy Subscription BTW ? You can give it a try, even for a month. Being able to learn from experienced producers and seeing them making tracks from scratch and creating sounds & effects could be very beneficial IMO. Not trying to sell anything here, just saying that it's a great way & place to learn
For this specific track and the Midi notes for the Lead & Bass layers, check this video on YT, the guy has got a FB link too, so you might be able to get more info about how he reproduced the sound and which synths plugins where used. But again, think about joining S.A as a subscriber, there's so many things to learn !
Hope this helps,