This is a good guide and goes over storage, charging and connectors. But charge at 1C only, so for example 5200mAh would charge at 5.2a, and a 1400mAh would charge at 1.4a.
Avoid Overlander LiPos, from what I have heard and seen, they puff up quickly and easily. The chargers seem to be SkyRC rebrands, so they should be fine.
You also need a charge lead for whatever connector your LiPo has, it needs to be an XT60 female to (your connector). Unless your LiPo has an XT60 on it.