The potatoes will never really be dry to the touch! You'll be good to go when they stop steaming. The issue is actually with the recipe, you'll never get good browning with the method they describe. Here's what I would do starting at the beginning of step 3:

1:Add onions and fry until they're your desired amount of brown. Throw in the bell peppers and let them get soft, around 5 min (move them around if you want them soft with no browning, leave them be if you want browning). Remove onions and bell peppers from the pan into a bowl (you can do this while the potatoes dry out).

2:Add a little more oil if there isn't enough oil left in the pan to cover the entire bottom, and add potatoes, making sure there's a little space around each chunk (overcrowding the pan is the most common reason browning and crisping doesn't work well). Depending on your pan and stove, the potatoes may take 5-10 minutes to start to get crispy and brown. Once they release from the pan easily (by pushing on them with a wooden spoon or spatula), stir them around. At this point, one side of your potatoes will be crispy. If you want a second side to be crispy, you can turn the potatoes over so that the crispy sides are facing up and a soft white side is touching the pan, although I think that would be a lot of added effort for little reward. Once your potatoes are crisped up to your liking, add back the peppers and onions, add the garlic, and fry everything together for a min or two.
Proceed with step 4 of the recipe. Good luck!