Car wouldn't start. No dash lights nothing. Changed battery fuze got dash lights

FIRST- won't crank---OR won't START??BIG difference! When you turn the key to the 'RUN' not 'crank' position , and just leave it , does the green 'key' stay lit and blinking , or does it come on briefly and go off and stay off? ALSO -- What 'battery fuse' was replaced? What amperage or was it a 'multi-fuse'??