If you're not doing an oatmeal stout, and you're just using pale malt and other types of barley, then you could do a standard 152-155 mash for 60 minutes or so. When you're using well-modified (barley) malts, you don't need to perform a step mash. Single infusion is fine at those cases. You may want to do a mash-out at the end of your mash, though. You can do this by infusing an amount of boiling water at the end of your mash, or you could collect an amount of runnings, then boil them, and add them back into the mash for about 15 minutes. Your target mashout temp is 170.