P,
MLF is a slower process than AF and it'll take longer to get going. Also, the bubbles are smaller, the residual sugar is less, and the MLB don't generate nearly as much CO2 as yeast. Keep the temp up, the O2 exposure down, the pH level above about 3.3 and you should see results soon. Also, some MLB nutrient (not yeast nutrient) will help the process along.
P.S. I just noticed you said you added MLF yeast. I assume you meant MLF bacteria because it's bacteria, not yeast, that do MLF.
Fred