Work on the U face initially. Use commutators to move center pieces from other faces to U.
Ensure that the color pattern you input into the solver matches your cube's scheme. On the 7x7, the fixed center determines the color of the face. 7x7 cube solver
: Once centers are secure, the 60 edge pieces (5 per edge slot) must be aligned into matching "bars". This phase often involves the dreaded Work on the U face initially