Connect the positive lead from each ESC to the positive of the battery and the negative of each ESC to the negative of the battery. The positive wire shoiuld include a fuse and the ON/OFF switch to isolate the battery.
The alternative is an ACTion P92 Distribution Board **LINK** which does all of the fusing and connecting and also provides a 5v supply for the receiver (if your ESCs don't have BEC).
Incidentally if your ESCs do have BEC then you must disable the BEC from one of them by removing the thin red wire from its plug. In these circumstances also don't use another receiver power source e.g. the flylead from a P92 or a separate battery.
Dave M