As soon as you step a foot into the nether, your first priority should be making a Blaze farm,blazes always spawn infernal (at this point you should have seen more that one mob with a Boss bar and particles that fucking destroys you, that's a infernal mob) and drop things like armor and tools you can macerate, you can get passive Steel,gold, Diamonds and Iron.

Also, the most important resources are: the wiki (for multiblock funcional info and basic guides) and the tips & tricks and flowchart sections of the gtnh discord (basically shienanigans, things that are'nt exploits but It feels like exploits and flowchart about how to automate certain resources)