Each number usually represents a hole on the harmonica
Blow notes are often shown as plain numbers
Draw notes are often shown as numbers with a minus sign or a preceding apostrophe, depending on the tab style
Example: 4 means blow hole 4
Example: -4 means draw hole 4
Example: 4′ may also mean draw hole 4 in some tab systems
Chords are played by blowing or drawing multiple holes at once
Slashes, commas, or spaces may separate notes or indicate timing
Repeated numbers mean repeat the same hole
Longer dashes or spacing may show note length
Numbers above 10 may indicate higher holes on larger harmonicas
Always check the tab legend if one is provided
Match the tab to the harmonica key being used
Read the tab from left to right in playing order