You should look at your BMI and then note how many pounds are required to get you into the good range. From what you reported 5-7 110 gives a BMI of 17.2. The healthy BMI (body mass index) begins at 18.5 and goes up to 24.9 I would say a BMI of 20 is safe.
For you that means being 5-7 and 128lbs. To be in the exact middle of the range (BMI 21.7) you need to be 5-7 and 138.5lbs
As you can see from those number you should only be looking to gain a max of 28.5 pounds. Gaining weight is dangerous, and yo udon't want to create poor eating habits and take silly supplements (like Creatine) just to put on some pounds. Your main goal is likely a physique. SO do not focus on WEIGHT or you could put yourself in a bad place. Creatine is higly unnecessary unless you are already working out and lifting to an extremem level in which you would NEED creatine to allow you to lift more (for longer periods). Don't start scarfing down food and taking creatine and have it all get stored as fat.
If you want to gain weight you will need to build some muscle endurance first, and learn proper techniques for various styles of weight lifting. Most people can NEVER lift heavy because they hit a wall where their technique does not allow them to withstand using more weight. They unfortunately do not realize that there technique sucks. So, start with lower weight and higher rep stuff, learn good technique (videos or a decent college-athlete friend can help you with this) then you should move to higher weights (lower reps e.g. 5), and try to increase the amount you lift every three weeks or so, but keep the reps the same.
Weight gain is a side-effect of becoming strong and powerful. DO NOT try to gain weight. Learn how to become stronger. If you just want to LOOK ripped, again gaining weight is not the place to focus your attention.
There are many articles about muscle building. In general, AFTER you've lifted and made tears to your muscles, you need to provide them with proper building materials to repair themselves. the window for "after" is as small as 45 minutes, and for building materials you should eat protein.