The benchmarktool as you know it from the STB is not yet present. The current advice is to setup a trade-bot and leave it running for a while non-activated. Using the "Current signals" it is possible to see when trade-command should have been send. This is the current way to benchmark.

I did the same while writing the first help pages of the indicator, you can see it here:
https://www.haasbot.com/indicator-rsi/
https://www.haasbot.com/indicator-stochastic-oscillator/

However as stated before this is not the real benchmark tool. We are working on something much better. I can not fully disclose yet, but think in the direction of auto-tune capabilities. Maybe (i am not fully sure!) the first parts will become visible coming on the update of monday.