Close the slow cooker and cook on low for 8 hours, or high for 4 hours.
This is outside of authenticity, but, if you want to thicken the gravy a bit, mix the (optional) corn starch with 1/4 C of water and stir it into the juices 30 minutes before you finish cooking.
1 Tbsp Corn Starch
After cooking, you should traditionally shred the beef with forks. I prefer to cut it or break it up into 2-3 inch chunks.
Serve this pot roast over mashed potatoes, rice or noodles, drizzled with the gravy and garnished with the peppers.
Notes
Experimental idea: switch the pepperoncini peppers with pickled jalapeños or the Mexican-style pickled jalapeños and carrots.