This is the optional quest's hint. Advance the main plot and you'll get access to the location with the extract. It's impossible to miss.
Thank you <3 i gets this
''Sr my English not good''
Humm sorry i think i don't know serana where can you help me again :'(
Use the help function from the on-map menu and Ada will tell you what you need to do. Sarana is in the deep mine location. The only one with lava on the second island.