Prusa i3 First print z axis not raising extruder during print

Hi I just finished building a prusa i3 from replikeo and have been trying to get a successful first print but when i start the printing of a cube it doesn't raise the extruder up to the second layer or the third. it drags it through the first layer and pulls it off of the bed. Any idea? Using the manual z axis movement buttons i can raise and lower and home it just fine but once the print starts idk what the deal is. Im using marlin firmware and printerface software as well as slic3r to slice things up. if you have any other questions please let me know id like to get this thing operational soon. Thanks in advance!

Have you calibrated your axis (x,y and z) and tested them? Eg. 100 mm movement with pronterface is actual 100 mm.
Extruding not to much filament? Measured the filament diameter and calibrated the extruded length?

What is your layerheight?

Ok ive calibrated everything but the extruder (i am about to do that) and the z axis goes up 1 mm when i tell it to do 10mm. can you help me fix that? y and x axis work fine 100mm=100mm. Layer heigh is .3 mm

Calculate your steps/mm here [prusaprinters.org] and put the value in config.h in marlin.

Perfect! Thank you a ton! I really appreciate it! It printed the cube successfully! The z axis steps per mm like you said in the firmware were wrong and ive got the correct numbers in there now! Thanks Again