Let’s break down the process into easy-to-follow steps.

Step 1: Cook Potatoes. Place the peeled and quartered potatoes in a large pot and cover with salted water. Bring to a boil. Reduce heat to medium-low and simmer until almost tender but still firm, about 15 minutes. Drain and finely chop the potatoes.

Step 2: Cook Corned Beef. Cook the finely chopped corned beef in a large cast iron or nonstick skillet over medium heat until the fat begins to render.

Step 3: Add Aromatics. Stir the chopped green onions, salt, and pepper into the beef. Add the crushed garlic and butter. Cook and stir until the butter is melted and the garlic is fragrant, 1 to 2 minutes.

Step 4: Add Potatoes and Salsa. Stir in the finely chopped potatoes, roasted tomato salsa, and a pinch of salt into the beef mixture.

Step 5: Form and Cook Hash. Pat the mixture down in the skillet with a spatula and divide the hash into 4 sections. Cook, without stirring, until a crust forms on the bottom, about 5 minutes.

Step 6: Flip and Cook. Flip the sections and cook until a crust forms on the bottom, about 5 minutes more.

Step 7: Repeat and Serve. Repeat the cooking and flipping process, flipping every 5 minutes, until the hash stays together and has a golden crust, 10 to 15 minutes.

These instructions are very clear.