Is there training available for oyster mushroom farming for a beginner?

Yes, and taking proper training first is the smartest thing you can do, because mushroom farming is more about technique and hygiene than money. Good places to learn include the ICAR Directorate of Mushroom Research (DMR) at Solan, which runs mushroom training, your nearest Krishi Vigyan Kendra (KVK), and State Agricultural Universities, many of which run short hands on mushroom courses. Some State Horticulture and Agriculture departments and reputable established growers also offer training. A short hands on course where you actually pasteurise straw, spawn bags and manage a fruiting room is worth far more than only watching videos. Ask your KVK about the next course dates, fees and whether spawn supply support is given. Learn on oyster first since it is the easiest, then move to other types.