Mana bar is like health bar: with CurrentHealth,* MaxHealth* and HealthRegen but now as CurrentMana, MaxMana and ManaRegen.
How Add Mana attribute:
"Open “Stat_Name” inside CharacterSystem/System, and click “New” (three new names) and type in name for each new attribute ‘CurrentMana’; ‘MaxMana’ and ‘ManaRegen’
Then open “CharacterSystem” blueprint in the CharacterSystem folder.
In the defaults, expand the Stats array, and click the + symbol next to it, to add a new element.
For the new element, select your newly created attributes names as Stat_Name (‘CurrentMana’; ‘MaxMana’ and ‘ManaRegen’), and set the default value, per level scaling and cost.
now you have added a new attribute to the system
For mana regeneration you would do the same, but also in the CharacterSystem blueprint’s Event Graph you would want to copy the Health Renegeneration part, and change the Stat in the nodes to ManaRegen."
To add mana bar in your hud the process is equal the health bar, but with bind in ‘CurrentMana’; ‘MaxMana’ and ‘ManaRegen’.
If you have any doubt see how health bar was created