However, since I have barely touched my flute for 2 years, I lack any semblance of an embochure and can't even spit out a proper 3-octave chromatic scale

I'll definitely be practicing my overtones and scales; I also have all my old band music as well as some books I never really got through. What else should I be doing? (lessons with a teacher are currently not an option for logistical reasons)
Also, if it makes a difference, I played on a Selmer student flute for 4 years then upgraded to a Trevor J. James Cantabile II
Sorry for the novel, and thanks in advance!