、。
Not only does she have to attend the funeral, she has to make all the arrangements.
Literal
She [topic-は] funeral [in-に] participate not-only-でなく, all [genitive-の] arrangements [object-を] make-must.
Three patterns. ~だけでなく ('not only X, [but also Y]') is the standard non-exhaustive pattern for adding more obligations or facts. つけなくてはならない is the obligation pattern ~なくてはならない ('must, have to'), in this case applied to つける ('attach, set up, finalize') in 段取りをつける ('make arrangements / nail down the plans'). 葬儀 ('funeral ceremony') is slightly more formal than 葬式; both work. The combined sentence captures the heavy weight of taking on funeral logistics, often borne by the closest surviving family member.