First off all: Nutrition

In order to stay Healthy and be able to exercise and build muscle, you need to Eat Healthy - No surprise there.

Each day you should be consuming at least 5 servings of Green Leafy Vegetables.
Spinach, kale, collard greens or broccoli are all great options.
Also you should be getting around 80% of your calories from Carbohydrates, which are the preferred fuel source of your body.

You should try to eat as many Whole, Plant Based Foods as Possible.

Research: HCLF Vegan Diet

Carbohydrates and Fat

If you are trying a Vegan diet or you are eating a standard diet, this implies to everyone. You need to eat carbohydrates and very low amounts of fat in order to live healthy and build muscle properly.
Any yes, you can technically build muscles on a high fat ketogenic style diet, but that cause the protein in your body ie. your muscles to break down and convert into amino acids, which will then be turned into glucose - the fuel for your body.

Video by HappyHealthyVegan on the Right Fuel For your Body:

Calories In vs Calories Out principle

Everyone has heard of the Calories In vs Calories Out principle.
The more calories you eat, the more calories you have to burn to maintain or lose weight.
If we are to believe this principle, then high fat diets fail immediately, as Fat is over Twice as calorie dense as Carbohydrates.
Because of this factor alone, it is way easier to overeat fats than carbs.

High Carbohydrate foods also fill you up better and for longer, because of the High fiber content and Low calorie count. And sorry to disappoint, but no animal product has fiber, since animals are not plants.🌿
And Carbs aren't fattening, Fat is!

Pretty much all the Carbs you eat will be converted into Energy or stored as Glycogen.
And in most cases, excess carbohydrates will just be converted into body heat 🔥.

Fat on the other hand is almost directly stored into adipose tissue.
The Fat you Eat is quite literally the Fat You Wear.

Research referenced:
A satiety index of common foods
Fat and carbohydrate overfeeding in humans: different effects on energy storage

And Now to the Good Part.

Building Muscles 💪

Most of traditional bodybuilders believe that in order to build muscles, you need to be eating all of the protein you can possibly get your hands on mostly lean meats like chicken and fish and to avoid carbs, because carbs will make you fat.

Well we already went over the second point, so lets go over the protein needs of your body.

- Protein

The most important dietary factor in muscle growth is maintaining a positive Nitrogen balance. And since protein is the only macro nutrient that contains Nitrogen, and the majority of protein in your body is found in muscle tissue, a positive Nitrogen balance is a very accurate way of determining whether your body is getting are an adequate amount of Protein.

Research:
Maintaining a positive Nitrogen balance with Vegan vs Animal-based foods

How Much Protein ?

As a rule of thumb, if you are getting about 10% of your daily calories from protein, you are getting a sufficient amount of protein for building muscle.

If you want to be more specific and are leaning out and trying to build muscle at the same time, you may consider the following study by Eric Helms, which states that a Protein Intake of 2.3-3.1 g per Kg of Lean Body Mass is ideal for building muscle and losing fat at the same time.

Research referenced:
A systematic review of dietary protein

Optimal Set And Rep Range

As long as you are lifting fairly heavy, meaning above 60% of your One Rep Max(Meaning the heaviest weight you can lift with proper form), Reps and Sets don't matter that much.

So just lift heavy and focus on form and you will build all the muscle you want.

And if you don't like going to the gym, I would argue that calisthenics is a even better option, since you get to go out in nature on some fresh air and sunshine, which will make you feel so much better than going to the gym. But it all depends on the type of person you are.