If you do season the pan, the most important thing is to wipe off all the oil after applying it. You brush the oil on and then wipe it completely dry. It should be dry to the touch and matt, not shiny. You should not be able to see ANY oil. The microscopic invisible bit of oil left is all you want. Only then do you heat it. The temperature doesn't matter much. 180 C or so in an oven is what I've used. The kind of oil used also doesn't matter. For best results do the whole thing 3 or more times. If you bake a visible layer of oil onto your pan you're not seasoning it, you're just covering it in burnt crap.
And it's optional!
Note that the above is for skillets, which self-season because they're used for frying. (Hence "seasoning" - i.e. using them for a while.) The story is very different for some other things. For example, we have a dutch oven used for baking bread, which is not an oily process. For that you really do have to season. Ours came pre-seasoned but it rusted after an unfortunate baking mishap and I had to electrolyse it and then give it 5 rounds of oven seasoning (as described above), after which it has been a zero-maintenance workhorse.
Griddles are absolute fucking bastards and will ruin your life.
If you ever do electrolyse any cast iron (it's great fun and will restore anything), A) pay a few quid for graphite electrodes (overgrown pencil leads, available on Amazon), rather than using an old stainless steel knife and producing hexavalent chromium (Erin Brockovich's favourite chemical) and B) use a bench power supply because nobody sells the kind of car battery charger all the online tutorials tell you to use any more (they're all pulsed ones now, completely useless for electrolysis).
I then dry it with a towel, heat up the pan with Avocado or Bacon grease until it almost starts smoking. I then use a paper towel to wipe out the pan and it stays on the stove until the next use.
Of the pans I have now (bought over the past 2 years), 3 are seasoned well enough that they’re effectively non-stick.
Lmao. Hapless beginner follows your advice, decides to scramble some eggs on day 1 with his badly-factory-seasoned Lodge pan. Egg glue now encrusts his shiny new pan. What do? Wash with soap? BAD NOOB - that's bad for the seasoning. Scrape it off with steel wool? BAD NOOB - that's even worse for the seasoning.
(If you do this, fellow noob, I think oil + a scrubber sponge got me out of the predicament)
Eggs pancakes, fish, no problems.