There should have been no exposed contacts to touch and burn out. You need to use the female part on the ends of any parts that will be live. If you always use female then no matter how many things you plug in one after the other the ends will always be covered. (I am not sure if I have done a good job explaining that). The male ends go onto the part you are going to plug in, so starting at the battery you plug in the ESC, then the motor, so your motors (or whatever the last thing in the line is) should all have male connectors.
Note: there are exceptions and if you end up using XT60's or EC5's etc then the problems is almost totally eliminated as both sides are covered once you have assembled the connector.