There are different builds for Diablo 4 Barbarian depending on your playstyle and preference. Some of the popular builds in Diablo 4 Open Beta are:
Hammer of the Ancients Barbarian Build:
This build focuses on using the Hammer of the Ancients skill to deal massive damage to single targets and stun them. It also uses Rend and Rupture to inflict bleeding damage and Pressure Point to increase your crit chance1.
Rend and Rupture Barbarian Build:
This build uses Rend and Rupture as your main source of damage, applying bleeding to multiple enemies and increasing your damage output. It also uses Whirlwind and Upheaval to deal area-of-effect damage and Leap and Steel Grasp to reposition yourself and pull enemies closer23.
Flay Barbarian Build:
This build uses Flay as your primary skill, which allows you to slash enemies with your weapon and generate energy. It also uses Lunging Strike to close the gap with enemies and Death Blow to finish them off. You can also use Rallying Cry to buff yourself and your allies and Leap to escape danger4.