Like any other 2s LiPo. Since it's "LiPo HV" you can set the end voltage higher... but there is no standard, so consult the instructions sheet that comes with the pack for max voltage numbers. I've seen numbers from 4.25 to 4.4, though seems like 4.35 is the most common today. You can also just charge it to 4.2 like a regular LiPo.

It's a 2s LiPo in the same form factor as a 6s NiCad/NiMh. That is irrelevant to charging. The point of this description is to let consumers know this pack will fit into a battery holder designed for 6s NiCads.