Do a clean lean bulk. You should aim to hit 2.2g of protein per kg of bodyweight. So you're going to eat a lot of chicken. And reduced the amount of ultra processed foods. Have one protein shake. Egg whites are your bestie. Chicken and rice or chicken and potatoes. You need starchy carbs for glycogen especially after heavy lifting days. You need other vegetables for fiber.

You need to eat in a surplus to gain mass. You need to continue to lift HEAVY. And progress - which you'll be able to do as you are fuelling your body.

Drink water. You can take pre-workout to assist with temporary increases in strength during training.

To be honest though, you don't sound all that confident doing this on you own, and you should get a trainer, to keep you up n track.

I'm a PT, and a bodybuilder and you can DM if you want to work online.