Hey man, welcome to the boards. Its always good to dismiss some bro-facts right out the gate to save you being targeted in the future; so for one, "hardgainers" don't really exist, its just a term people use when they think they are eating heaps and not gaining any mass. More than likely though is that you aren't actually eating as much as you think.
Its best, IMO, to get a gauge of how much food you need by googling TDEE calculator, filling in the required fields then add 200-500kcals on this number. Use myfitnesspal.com to enter in foods you commonly eat to create a meal plan focusing on nutrient dense foods first.
See if you make progress doing this regularly for a few weeks and then add/ subtract calories based on whether or not you are seeing the results you want.
Secondly, you are so new to the game that the first few months of "gains" is simply your neural system learning how to effectively perform the movement. You usually notice your greatest "strength" gains in this period rather than any real structural changes in muscle. IMO using supplements during this period is a waste as you will notice HUGE improvements in strength that you will directly attribute to supplements rather than a more efficient neural system and increase motor unit synchronization.