On lifting weights: there is an incredible amount of broscience and misinformation out there that may hamper your efforts. Some good resources:
https://www.youtube.com/watch?v=h5wHFpvwO6ohttp://stronglifts.com/madcow/Topics/Tr ... Primer.htmhttp://www.leangains.com/2011/09/fuckarounditis.htmlhttp://www.oldtimestrongman.com/strengt ... -j-steinerI suggest a book called Starting Strength if you're looking for a good resource for learning the lifts. There is also an excellent Youtube channel called "Alan Thrall" with form videos for the basic barbell movements.
It goes without saying that you should ignore most of the nutritional information that you'll encounter in the links I've provided. The only important things for your situation are:
1.) Eat at a 10% caloric surplus. This will ensure that most, if not all, of what you gain will be muscle mass. Drug-free lifters can only synthesize about 1/2 pound of muscle per week maximum, so this should achieve that. Basically, find your TDEE (find a calculator online), and multiply that by 1.1. If you're not gaining weight after a few weeks, bump that number up by a few hundred calories.
2.) I'm going to catch flak for this, but protein should be at least 1 gram per kg of bodyweight. That's roughly .42 grams per pound of body mass, I think. A standard McDougall diet should provide this. Throw some legumes in if it isn't.
Onto programming, this is where most people get derailed. For a novice, the following programs work well:
1.) Starting Strength
https://www.jackedfactory.com/starting-strength/2.) Stronglifts 5x5
http://stronglifts.com/5x5/3.) Reg Park's 5x5
http://oldschooltrainer.com/reg-parks-beginner-routine/These should serve you well until you can squat 315, bench 225, and deadlift 405 for a set of 5 reps.
You'll notice that these routines are pretty similar. In terms of time spent in the gym, Starting Strength is probably the quickest program, and Reg Park's is the longest. You can also look up something called "Ice Cream Fitness 5x5" if you have the free time to destroy yourself for 1.5-2 hours 3x a week. If you don't like 5x5 style training, you can head over to reddit.com/r/fitness/ or the bodybuilding.com for something a little different.
Disclaimer: I'm weak as fuck and only like 3 months into my own training. I'm gaining strength/ muscle pretty rapidly and am already stronger than many "veterans" at my gym, though, so I might actually be right about all of this. All I know is that there is an incredible amount of contradictory and confusing stuff out there, most of which doesn't work very well.
Edit: I almost forgot the entire part about gaining weight on a WFPB diet! If high-fat foods give you acne, then I suggest eating more flour-based foods like pasta, pancakes, bread, etc. Fruit smoothies are also good. Fruit juice and dried fruit are excellent as well. Remember: liquid calories are always easier to consume than solid foods. Exploit this as necessary. Your stomach capacity should slowly increase over time, so this process gets easier the more you do it.