The Smooth Set
Both 50 ml rollers. Two different problems.
The Ingrown Hair Oil for a hair that's growing normally and can't get out. The Smooth Gel for hair that's growing perfectly well and isn't wanted.
This is not a routine, and there is no order. They aren't two steps of one thing, they don't share a mechanism, and using one tells you nothing about how the other will go. Most people only have one of these problems, and if that's you, buy the one product — it'll cost you $49 and we'd rather you were right than spent more.
The set exists because some people genuinely have both, usually in different places: bumps along a bikini line, and regrowth on legs they'd rather were slower.
Ingrown Hair Oil 50 ml plus Smooth Gel 50 ml. $89, saving $9.
Timelines differ: two to three weeks for the oil, four to six for the gel. Neither has been tested on people for efficacy — the reasoning behind both, with the evidence level attached, is on the ingredients page.