[Noobie Blade Dancer confused]

Hello.

I would like to ask what soul badge chest do i need from the dragon express (those you can buy with solar thingie) as a Light Blade Dancer?

Or should i just farm martial tokens and buy the legendary and fuse it?

After some digging i know i should use the Songbird as a light BD and fuse it later, but i'm still confused a bit about soul badges or how should i progress with the badges.

Currently i have the one from the story quest.

 

Thanks in advance!