Limbo
You pick a target multiplier. If the random result reaches it or goes higher, you win.
In limbo, you choose a target, say 2.00x, and place your bet. The game draws a result multiplier. Land on your target or anything above it and you get paid your bet times your target.
How the result is made
A usual provably fair method takes one float from 0 to 1 and converts it so your odds of reaching a multiplier m are roughly (1 - house edge) / m. With a 1% edge, you hit 2x about 49.5% of the time and 100x about 0.99% of the time. Exact formulas, rounding and the lowest possible result change from site to site.
You control the ride
Whatever target you set, the house edge stays the same. Higher targets just miss more often and pay more when they land.
Real-life example
You bet 5 $ with a 3.00x target. With a 1% edge, you win around 33% of the time. Result comes in at 4.21x? You get 15 $. At 2.87x? Your 5 $ is gone.