The established best practice for conversion in a lager mash using Pilsner malt is 90 minutes. Opinions differ regarding how well-modified modern Pilsner malt responds to a shortened 60 minute mash. You can get great lager with a simple 90 minute mash at 152F.
Most experienced brewers perform Pilsner mashes in steps, with 2 or 3 rests, each at a progressively higher temperature. Traditional Pilsner mashes involve one or more decoctions (easily performed if you brew ina bag by removing a portion of the mash, boiling it, and returning it) and this technique is one way to create the “step” mash temperatures. Step mash temps can also be achieved through the burner if you have a heavy bottom to your boil kettle, but some stirring is advised to prevent burning. Nowadays, with dry beers being favored, many people feel decoction adds too much sweet grain flavors, which the piilsner malt already has enough of on its own, as it darkens and concentrates the sugars in the wort.
If you are new to lager, and want to keep it simple, then 90 minutes at 152F or the Hochkurz method (45 min at 144F, 45 min at 160F, 170F mash out/sparge) are both reasonable options.
