I recommend doing it like so:
Find a wide open spot, or as wide open as it gets in the underworld

. Make a long line of bricks or platforms, at least 350 blocks long, but the longer it is, the better. You could place fireplaces along this line, or heart lanterns, but unless you’re in expert mode, I don’t think this is necessary.
Weapons:
Minishark(bought from arms dealer)This is the main weapon I use for its great DPS on the wall itself.
Sharanga(2x molten fury+10 hellstone bars) this will cost 40 hellstone bars total. The sharanga works great on “the hungries” because of its spectral arrows inflicting the cursed inferno Debuff.
Nights edge(fiery greatsword, jungle spores sword, lights bane/blood butcherer, maramusa) great against hungries if you don’t want to grind for that 40 hellstone.
Star cannon(minishark, 5 fallen stars, 20 meteorite bars) this is a very much viable option for damage on the wall itself, but it shoots fallen stars which are kind of hard to find in great quantities.
Armor:
Molten armor(45 hellstone bars) this is the only way, really. It has by far the highest defense of all the pre-Hardmode armor sets.
You would probably be able to get away with Crimtane armor or shadow scalemail in normal mode.
Meteorite armor has lower defense but makes the space gun cost 0 manna, so it would probably suffice.
Equipables:
Hermes Boots(found in underground chests) these are quite helpful if you have gotten to close to the wall and need to rush back a little.
You do you. Honestly, these are just my recommendations. Feel free to change and adjust however you feel necessary. Also, the wall of flesh is a pretty easy boss if you make the long line of blocks.