Here is a lesson on how to how to sing and play ukulele at the same time. Now, this lesson is to teach you how to sing and play at the same time. It focuses on the timing and nailing the specific words with specific changes. To really learn how to sing I recommend that you get a coach, but these general tips will help get you started. Check it out and at the minimum it will get you moving in the right direction. If this helps we also have a lot of other videos, how to play beginner songs, how to play the blues, learning the pentatonic scales, and all kinds of goods stuff.
How to play Brown Eyed Girl:
How to play Three Little Birds:
Ultimate Guitar (Chords to songs):