Hi! Glad to hear you're digging the SRD so far. As a rule of thumb that I use in my games so far, a point buy of 4 points during character creation is used for the Attributes. Every Attribute starts at 1, and then players can increase the Attributes however they want by spending 4 more points on them. Advancement lets them boost those up one more time in LIGHT, for example. Hope that helps!
Love the idea of a metroidvania game using LUMEN!