Well its easy to gain weight rather than loosing it, so yes u can gain 5-10 kilos a month, adding a weight training
program is a great step towards gaining some muscle mass.Now as far as supplements go , as the name suggests they are only supplements they will only help you when you have the right nutrition and workout program. Try to eat a 100gms of protein a day , plz do not eat junk food this is very unhealthy. Hit the gym 3-5 times a week and follow a mass gain program.
Eat big and eat healthy.So the bottomline is " you need to eat big to get big".
Train and eat consistently and you should be on your way to some nice gains.
Thank you and take care