I am a guy who haven't been working out(exercising) throughout my life. I live a very sedentary live, mostly at my desk reading books or using my computer. The nature of my field of work requires me to only sit at my desk. As opposed to what many people would think of me, I am not obese but neither am I fit. I am very thin and look somewhat scrawny. I am thinking that this is perhaps too unhealthy for a life. I've read a few of the answers on this site and it seems that most of the answers are suited for people who haven't worked out for years and have started to gather fats and would want to burn it. For me, I am too skinny for any visible fats.
I'm thinking how I should begin to start gaining weight and look less skinny, albeit in a correct and healthy manner; I reckon that an abrupt and incorrect way of starting out this goal will end up more harmful than helpful. So, I'm seeking for some advice on this.
I'm a 26 year old male and weigh 45kg. I feel like I'm very thing. What is a good way to improve my health? Is it a good idea to use power plank exercise machines for someone like myself?