IF you have never been on a motorcycle before go online and see when the next Motorcycle Safety Foundation (MSF) beginners riders course is where you live.
Its about $250 to $300 now, a three day course. First you need to get your motorcycle permit (easy test). You dont need to bring a motorcycle for the course, you get to ride one of theirs. All you need is a jacket, gloves, boots.. and a helmet if you can get one (some courses have helmets available).
The course is half class room training on riding, rules, and safety, and the other half of the 3 days is learning to ride, usually in a big fenced in parking lot.
Even if you have never been on a motorcycle before, and you have never used a vehicle with a manual transmission before, they WILL teach you how to ride in those 3 afternoons. Unless you really have no aptitude for it you will pass the course, and at the end of the 3 days you will have your motorcycle license.
You will also save 10% on your motorcycle insurance for the rest of your life.
The first time you do not crash your bike because of the things you learned in the course, it will more than pay for the fee.
There is a lot you need to check on the bike before you try to start it.
Check the oil level. If the oil is more than a few years old you will want to replace the oil and filter, because oil breaks down just sitting in a bike for a few years. You can run it for a little bit on the old oil, just to see if the bike will start, and to make sure there are no serious issues with the engine before you start buying new oil, filters, plugs...
If it has not been run for a long time you need to drain the fuel tank, and dispose of the old gas. Then look inside with a flash light and see if the tank is full of rust - if it is you have some work to do.
If not you can fill it with fresh gas and some carb cleaner, like Seafoam from Walmart auto section, and maybe you will get lucky and it will start for you... might need a new battery too.
Dont just jump on the bike and think you can ride it like a bicycle. There are a couple things you must learn first because your life depends on it.
1. motorcycles steer backwards - its called counter steering. You need to google this, watch videos, and learn all you can BEFORE you try to even ride around the block because if you try to steer it like a car it will go the opposite direction from where you wanted to go, and that never ends well.
2. motorcycles are self balancing, but only if the wheels are spinning. If you apply the front and/or rear brake hard enough to skid the tire the bike is going to fall over, just as if you stopped the bike and got off without the kickstand, and let it go: BAM!