One attempt refers to one 14-day evaluation phase. If you fail Phase 1, that counts as one used attempt. If you pass Phase 1 but fail Phase 2, that is another attempt used.
A complete evaluation from Phase 1 through Phase 3 uses a minimum of three attempts if you pass every phase on the first try.
The package duration (e.g. 2 months, 6 months) is the period within which your attempts are valid. Unused attempts expire at the end of the package duration.