help with vanjasts real navigation mod

[orangewhale]

Hi i've read Vanjasts real navigation readme titled SH3_RNM_usingtheGameMod and im still confused, ok i know how to find what course im supposed to travel using the protractor tool - it is subtract or add the angle onto or off 360 degrees right? and thats your course (tell me if im wrong) - i use speed/distance calculator on the internet to find out how long it will take to travel that distance in kilometers at X many kph, but how do i use the sextant, i mean i don't even know what button to press to turn it on. Basically i either need someone to help me a little, or point me to a link that has a guide that is more in depth.