The basic astrological Rudraksha
combinations, here are for all 12 Rasi lagnas:

Aries - 3, 5 and 12 mukhi
Taurus - 4,6,7 and 12 mukhi
Gemini - 4, 6 and 7 mukhi
Cancer - 2, 3, and 5 mukhi
Leo - 3, 5, and 12 mukhi
Virgo - 4, 6 and 7 mukhi
Libra - 4, 6, and 7 mukhi
Scorpio - 2,3,5 and 12 mukhi
Sagittarius - 3, 5, and 12 mukhi
Capricorn - 4, 6, and 7 muhki
Aquarius - 4, 6, and 7 mukhi
Pisces - 2, 3, and 5 mukhi

Please bear in mind, these are most general recommendations and also
that no single Rudraksha or combination would be detrimental... only
a matter of targeting the planetary energies you want to balance.
Depending on the relative strength of the planets involved, you could
wear more of a particular mukhi bead than others, if for example that
planet were quite weak, but otherwise benefic.

There are also more specific ways to choose based on planetary
periods, transits, yogas, and many more considerations that require
individual chart analysis.