The best type of ukulele for a beginner is a concert ukuele; the sound is usually more full than a soprano, and the size makes it easier to play. There are many types of ukueles, but the basic ones are soprano, concert, tenor and baritone. Research what your ukulele will sound like and how you will play it before making your final purchase.
Now that you have a ukulele you will need to make sure it is in tune. Normally ukuleles are tuned to GCEA. When holding a ukulele the 4th string, G, is closest to you, and the 1st string, A, is fathest from you. Over time your ukulele will fall out of tune.
Tune your ukulele along with a piano (or an app) by playing the note that accompanies the string (shown in photo)
If you are left handed, the tuning will be the same.
If you want the tuning of your ukulele to change, you should invest in a capo. A capo is clamped on the frets to raise the intrument's tuning.