My advice to you would first be to read some articles on training and educate yourself. Learning about different exercises and their proper form is essential to building a good foundation of both your knowledge and physique.
Search the forum for different splits (the way you break up your muscle groups and work them), and decide what might be the best for you. Right now, you probably have little idea about your body, what your recovery is like, and what methods are the most beneficial for yourself. Everyone is different and the only way to definitively understand what works best for you is to try new things. The way you pair muscle groups DOES matter, and you should research how working different muscle groups with one another effects your recovery and growth.
While reading up on these different areas, keep in mind that there are basic exercises that you should be performing in order to build a good foundation. In my opinion, a beginner needs a good foundation of compound exercises in their regimen. These exercises are the opposite of isolation movements, and work multiple muscle groups. For example, be sure to include squats, bench press, deadlifts, etc.
Finally, if your goal is to gain size, research DIET! Visit the nutrition section of this site and be sure to read the sticky on bulking. While training hard is a large portion of building muscle, you cannot neglect your diet. Once you read through those articles, form a preliminary diet for yourself and post it in the nutrition section. We can then help you through it.
Good luck, and ask questions along the way!
__________________ Strength is understanding that your power is both physical and emotional. - Henry Rollins | 
