What it means
A kendra gives action. A trikona gives fortune. When a single planet rules both, Parashara calls it a yogakaraka: the planet that links effort to luck on its own.
Only some Lagnas get one. Saturn for Taurus and Libra. Mars for Cancer and Leo. Venus for Capricorn and Aquarius. The other six Lagnas have none, and this rule returns no match for them. That does not mean a bad chart. It means this tool does not apply.
When the yogakaraka itself stands in a kendra or trikona, the chart is read as having a dependable engine. Tradition expects its dasha, the stretch of years it governs, to be productive.
Look up your Lagna first. If it is one of the six, run the rule. Then lay the timeline of your life against that planet's years.