The gym can be scary to newcomers but don't ever be afraid of the dudes that are stronger than you: they were scrawny at some point just like you. Gyms exist for the purpose of self-improvement, so their communities have a good attitude and long-time gym rats would be happy to lend you a spot should you need one.
Until you get close to reaching your genetic plateau, there's no need for fancy workout routines. Just do bench, squats, or deadlifts every day, and supplement those with workouts that hit the same muscle groups. For example, if you bench, supplement with shoulder and arm dumbbell exercises. If you deadlift, supplement with pullups and rows. If you squat, supplement with more leg work. The reason these three workouts should form the core of your lifting is that they hit your central nervous system the hardest and work the largest amount of muscle; your nerves will get steelier quickly and you'll also hit the maximum amount of growth hormone output. Basically, you'll get really strong, really fast.
I'm still a noob when it comes to eating healthy, but for getting stronger, try to match your body weight with grams of protein daily. Try not to use powders for more than 50g.