the tablet tells a story and tell wisdom ex.(yan and yin working together) THATS IT! the jus apply the stroy to whats going on around them, nowhere did it say how to get the MS or EMS or even the rinnegan smh the EMS came from madara's life story his brother was dying and he wanted to aid his brother in defeating hashi so he shared his power, he didnt kno it was later going to be called EMS they jus noticed after they never lost light like normal MS, lol thats like saying obito as a kid read the tablet and jus knew to give p his eyes to give power, NO they kno there eyes are power and if they wanna share it thats what they do.