Greetings John, and a hearty Welcome to Chordie!
There are several good tutorials out there to teach the basics of TAB including some right here on Chordie. Take a gander at the Resources area.... that being said, When looking at a tab score, you will see patterns of fingering depicted that likely relate to chord shapes that you are familiar with (especially if you have the barre chords down). Basically you are looking at a numeric guide to where the notes are on the fretboard. Horizontal lines represent the strings high to low/top to bottom, and the numbers represent the fret where each string is fretted. Stacked it's a chord strummed, and offset is individual notes picked in the sequence they appear.
What is lacking is the note name and naturally the time signature that you would get from standard notation (like piano sheet music).
The rest is familiarity and of course practice! (darn-it!).
Once again Welcome Aboard! and hang on it just gets better and better!
"what is this quintessence of dust?" - Shakespeare