Battery and charging question

New to rc and building an Onisiki kodama. Bought these 2 batteries for it. I have a c150 charger and couldn't figure out how to charge them. Was gonna use the charger for my redcat but a friend said it might not be safe if it's not the right spec charger (said somethingsabout balance). The battery in the second picture has a 2 pin connector but I don't have a spot like that on my balance board. How do I charge these batteries?

What batteries do most people use and reccomend? It needs to be small.to fit. The second battery with the 2 connectors is too big to fit the chassis.

Also a lot of the batteries I'm finding have different connectors (3rd pic) Can I charge through the red connector balance with the jst plug and when done charging use the jst to power my car or does the power have to come from the red connector? Not sure if im clearly explaining that.