The key to lamb intestines is to braise them. Heat and spices are both important. Generally, many restaurants or meat processing companies that make whole sheep feasts have their own secret preparation methods. And each chef has a different production method.
In fact, just making sheep intestines is a very narrow path. To make it, you need to understand the whole sheep clearly and make the whole sheep into a perfect delicacy.
These techniques are usually not learned in ordinary cooking schools. You have to go to a restaurant to learn from a professional chef.