Alrighty,
Start with both nap and night sleep. Switching back and forth will just confuse her. Have a set wind down routine for naps and bed time.. the routine will help her. Do your best not to sway from the sequence of your nap and night sleep routine.
If over 4 months, you may have to do pu.pd to help her settle, if under 4 mos, then pat-shush. Stay with until completely asleep-- we will wean that later.
It will take a few days, just as long as you are consistent and calm as possible. If she had healthy sleep habits, they will return.
Good luck!