It depends on the resources at hand. Such as manpower, funds and so on. For example, there are many experienced employees in your enterprise. You can form an internal lecturer team, formulate selection criteria, and select some of these experienced old employees to be internal lecturers, who will assist the enterprise in training new employees. If there are few old employees in your enterprise, but they are rich, you can take E-LEARNING or hire external lecturers for training. These are all ways to buy external knowledge for training through the learning platform, but this method is actually a little divorced from your concept of training college. It is best to build an internal team of lecturers.