[Original notes translated into English from original recipe - see URL]
The amount of mash and rinse water you should use depends on the equipment and the method you are brewing with. As an estimate, we can say that you can use 16 l of mash water and 13.5 l of rinsing water for this beer. Some brewing machines (e.g. Speidel Braumeister) may require larger amounts of mash water. Always check the manual of the equipment you use.

In this beer, a more advanced mash scheme might be worth trying:
55 C (131F) for 15 min (protein step)
63 C (145F) for 45 min (beta-amylase step)
72 C (162F) for 15 min (alpha-amylase step)
77 C (170F) for 5 min (knead)

OR:
Mashing at 66 C (151F) for 75 min. Mash at 77 C (170F) for 5 minutes if you have the opportunity to increase the temperature in the mash.

Cool down to 9 C (48F) before pitching the yeast.

Fermentation at 10 degrees until 2/3 of FG is reached (typically after 10-14 days). Then increase gradually (approx. 1 degree per day) to 17 degrees. Keep at 18 degrees for 2-3 days. Then lower to 10 degrees or lower before bottling (20-28 days in total).

Yeast alternatives: WLP830, WLP838, Saflager 34/70

Modified original recipe with details from another and changed mash to a step schedule with three decoction steps. The decoction steps are to be conducted sort of in parallel with the mash step before it.

Using long, insulated gloves (https://a.co/d/795ZKxH), I dipped a quart pyrex measuring glass into the mash tun and removed four scoops of drained mashed grain. You still want some liquid but it should be a thick mash. I roughly measured 3 gallons of milled grain in my grain bucket at dough-in so that is why 4 quarts to be decocted (1 gallon which is roughly 1/3 of grain)

I put this in a 5.5 quart pot sitting on an induction hot plate set up beside my mash tun. It would take about 10 minutes to get to boil. So generally, I would get mash tun to temperature for a step, wait about 5-10 min. and then scooped out grain to be boiled. Once boiled for 20 min. the mash step time would have expired and I would put the grain back. The extra heat of boiling would help raise to the next step although it usually took a little more heat. Once at the next step temperature, wait 5-10 minutes and repeat. Ultimately, this added 1-2 hours to my typical brew day time.

The triple decoction did raise SRM so I did not use the Carafa Special III that was in the original recipe. Brewer's Friend is calculating SRM from the grain bill but with decoction, I estimate it to be around 18 at the end of the boil.