1, It may take 3-4 hours to charge your battery. The light will turn green once charged.
2, The only Tip is to keep the right way up so the LE does not fallout.
These are a interference fit & a few are loose from the start. Or if the LE has been in & out a few times.
I hope it does not cause you a problem...
A tiny smear of epoxy deposited with a tooth pick at two points around the edge will keep it in nicely. Not too much as you may want to take out the board and 'upgrade' when the next, more efficent LED is invented. Don't use superglue as it gives off a vapour when setting that may fog up your reflector and lens.
Loads of people want to moddify their lights, that's why they aren't glued in.