First you have to get up in the morning after a good sleep (7,5 and more hours)
You have to eat enough food rich for nutritions like proteins and carbohydrates (rice and chicken, eggs and etc. 4 times a day or more) so your body will have the oppurtunity to build muscles from something (you need 1.6g of protein for 1kg of your bodyweight and the same amount of carbohydrates if you want to gain muscle)
When you have your sleep and eating well managed you can go to the nearest gym, if you want to benchpress more, you have to work on your chest and triceps (you can google all the exercises and tips on the internet nowadays) but you should train all the bodyparts, for a newbie its ideal to have trainings 3 days a week for 1,5 hour for 3 bodyparts.
Its all about eating enought and clean, sleeping well and tearing the muscle. Fitness lifestyle will make your feel a lot better. 2 first month can be tought but after that its all great fun, passion and like a drug a little bit. At the start you dont really need to take any supplements, you will gain a lot naturally, you can consider investing in them after some months of workout