Prusa mendel i2 extruder settings

Hello all sorry but I am new to this and this is probably a silly thing to ask but, I have set my fireware for my x,y & z stepper motors but have no clue how to work out the vaule for the extruder.

I have a Sanguino 1.3a board with Atmega 1284p running Marlin firmware.

So far my setting look like this (just for information really)

#define DEFAULT_AXIS_STEPS_PER_UNIT {72.7442,72.7442,200.0*8/3,760*1.1}
________________________________________(X)_____(Y)____(Z)______(E)

Just need help with the last equation please.

Start with Richrap

[richrap.blogspot.com]

There is also plenty of info in the Wiki and the Google Machine on the tubes of the Internet... (that's a cheeky way of saying Google something like "reprap extrusion calibration") Good extrusion is a key. You'll need to know how it works and not just what to plug into the firmware.

Thanks, I will have another look at google but when I looked before it sent me all over the space continum

I also understand how the extrusion works its just I am not sure how to get the feed rate at a usable rate, so far I have just been getting no feed due to feed to high so not melting my pla or just running out of hot material.