The Shva appears as two small dots in a vertical line beneath a Hebrew letter and is used to indicate that either there is no vowel for that particular Hebrew letter, or that there is only a short half-vowel, sounding like the short "i" in the English words "it," "is," and "in." These two forms of the Shva are known as the resting Shva שְׁבָא נָח (no vowel sound) or the moving Shva שְׁבָא נָע(a short half-vowel sound).
Shva Nah Reinforcement Games
Review Shva Nah Rule Alef and Beis