Basically it's Positive to red Batt wire and Negative to black wire.

Keep Cap leads as short as possible, insulate as best you can. Keep caps close to the ESC rather than the battery.

You should stick to the same Voltage Value as the original, you can add as much Capacitance in Parallel as you want as the value is added as you add caps in parallel.

See the Etti esc's on Ebay. They build a PCboard that is soldered right to the battery I/P leads. The use the same voltage values as the original esc caps do...

Some people just use a pair of plugs to plug a bank of caps into.