There is many useless info out there so I aim to quickly and in a minimal style explain (almost) all that you need to know to get buff naturally.

Exercises

Aim for a full body or PPL (Push pull leg) split (never do body part splits).
Exercise at least 3 times per week, optimally 5
Focus your exercise selection on compound movements (bench press, squats, overhead press, deadlift) + freeweight/cable isolation
Don't buy a personalized plan, find a suitable plan for free on YouTube or make your own
Use double progression for weight progression: Double progression info video
Go for a 5 to 10 rep (repetition) range and 3 to 5 set range, focus on training to failure or 1-2 reps short of failure (more safe)
Browse musclewiki for exercise selection and video instructions

Diet and supplements

Almost all supplements except of protein and ok formulated pre workout are scam and a marketing trick (don't waste money on creatine).
Use calorie calculator to calculate your daily calorie intake that you need to bulk or cut. There is also a calculator on this site for needed macros.
Don't let get the calorie numbers get into your head! Just bulk.

Progress in slow and will slow down at about one to two years of training.
Most important part is to stay consistent at both going to the gym and dieting.

Good YouTube channels/influencers: