Look at the beginning of your keyboard tabs and see what information is included. The numbers at the beginning of each line on the left-hand side denote octaves. Middle C (C4) is the beginning of the fourth octave; the higher the numbers are, the higher the octave. There may also be an R and L (or RH and LH) at the beginning of the rows to denote which hand should play each note. The rest of the rows will contain lowercase letters representing notes, with hyphens (-) in between to serve as spacers.
Determine which method your keyboard tabs use to denote sharps and flats. In general, keyboard tabs only use sharps to mark notes played on the black keys of a keyboard; this is to avoid confusion between the flat symbol and a lowercase b. Sharped notes will either be marked with a sharp sign (#) after the letter or as a capital letter (A, B, etc.), while lowercase letters represent naturals (the white keys).
See if your keyboard tabs include information about rhythm. This will be on the bottom line of the tablature, beginning with B, with numbers (representing the beats of a measure) lined up under the letters (representing notes). If your keyboard tabs do not include information about rhythm, listen to a recording or otherwise familiarize yourself with the rhythm of the music.
Note any other symbols that might cause confusion. Sometimes, chord names will be given in brackets (e.g. [D], [F#]) above the notes that make up that chord; this is not part of the melody, but merely an aid for analyzing chords and improvising other notes within the chord. In addition, "greater than" symbols (>) may be used in place of hyphens to denote that a note should be held out for a certain length of time.
Practice playing keyboard tabs on your piano---simple tabs first, with a single melody, followed by more complicated music which uses both the right and left hand and has multiple notes at a time. If you have any difficulties interpreting the meaning of keyboard tabs, check out the links in the References and Resources below for more helpful tips and practice materials.