This quest unofficially starts at Po in the Sonata Mountains. You can travel north from the center of Sonata, or Instant Transmit directly to Po. If you SAY 'What do you know about the Sonata Mountains?' to Po then you'll get a hint about the Resonance Shrines. This is also how the Konatsu being their quest for their Soul Weapons. You'll probably want to have at least 50m max before you start this quest, and will probably need considerably more PL to safely complete it, and there a few dangerous mobs that can still hurt you that are wandering in the mountains. The Ur Dragon is notorious for destroying newbies.
After you talk to Po, head back to the center and then east till you run into Talisein. You can also IT direction to him. If you walk to him SAY READY, and you'll be transported out. Mobs are aggressive here at night, and mostly non-aggressive during the day. This is a huge wide open area and navigation through it can be a bit daunting...
You'll start in the basin, find the exit NE out of this area. Keep heading north and then head through the northeast exit. Keep following the path northeast until you find a north (not NW) exit. Along this path or on the Frozen Lake are numerous aggro harpies, they are 50m PL, so avoid them or be ready to fight. Head east through the Lake following along the southern edge, and you'll quickly come along a SE exit. Follow that path that is labeled as a Winding River and eventually you'll come across a shrine that will give you a song like looking message. Head back to Po, or IT to him.
Head to the western Scroll Room, and go to the north to find Master Han. Follow his prompts... You will be tested on a bunch of scrolls, you can buy them from him by typing list. Fun Fact: these used to be located in the shelves but kept bugging out, so now he sells them for just 1 zeni instead. You'll need to read each scroll, or cheat by reading this guide. You can SAY POSITION UNASSAILABLE and skip to the end. Pick whichever you think is best in life for a reward. I think he may give you a Keikogi no matter what. Which is a forgettable layer 16 body item with a 10m PL requirement. You should also receive the Creation Scroll. He mentions four more shrines.
Head back to the Frozen Lake, and make sure you're flying or you'll fall through the water. You will also need way to breathe underwater or to be quick. From the entrance of the lake, A snow-covered Fisherman's Quay head NW 4 times, then Down 2 times, north, ne, e. Then get out of their quick by IT'ing back to Po. speedwalk rrrrddnqe from the quay.
Once you're back at Po, head to the northern room and find the next master on the west side. SAY resonance shrines, SAY prove? and you'll be given a sealed letter. Master Yarrow will tell you to go to the Rhyme & Remedy, which is located just NW of the center of Sonata
Find Allsong in the back of the Rhyme & Remedy, SAY BLOOM?, and then you'll be given a flower. This is a cool little mechanic that slowly blooms the flower as you fight. As long as you are in combat it can trigger so go to an appropriate gaining zone for your PL. Once it blooms head on back to Allsong.
Once you give Allsong the flower she'll teach you all about kitransfer! Which should unlock Split-form and Ki heal on your alist. There might be other requirements for these skills but I am unsure. Make sure Ki Heal is there and then head two east from Allsong and wait for a scene to play out. Choose an option and you'll be rewarded after they talk for a bit. And right afterwards you'll learn Ki Heal! You'll receive a new letter and head back to Master Yarrow with it and give it to him. There are three more shrines to seek out if you'd like, however this ends the portion for skills.
The easiest way to find this one will be with a speedwalk. From sherpa: speedwalk eeeeqqqnnnqnnnqrrwwnnnrrnnnnwnneesswwnneeteeqnn . If you want to walk there, IT to Sherpa/Talisein, head like you're going to the lake, but go NW at the fork, at the mining entrance go N into the hidden exit. The big area ahead spirals downward so follow it around twice, then go out the east exit, and to the NE to find the third shrine. Once you see the melody/music thing you'll know it is complete. Head back to Po once you've seen it. You'll find the next master in the eastern room Dojo.
When you're at Fumiko, follow her prompts. She'll ask you for a favor, and wants you to hunt down her student Messara. From the center of Sonata head all south, then east and open the first door to the SE. Head inside and SAY MESSARA to the Konatsu woman inside. After talking to her head NW and a couple rooms north, then eastward into the Training Grounds. Take your first south exit. SAY MESSARA at Ashira. After watching her story she'll mention Shadow Earth. But you will actually have to head to Bear Forest. IT to Lorren, or take the ships if you must. The entrance to Shadow Earth is just a bit NE of Lorren. SAY I've been searching for you.
You have a few options to say to Messara. Some will make her fight you. The last option at least causes her to leave without being aggressive. (say: 'What you will find in the Shadow Earth will destroy you.') Head back to master Fumiko. Follow the prompts for your reward.
To be continued.....