This is the 1589th most frequent Russian word.
составить
To compile, compose, draw up, or arrange.
Here, 'составить' is used in the context of creating or compiling a list of items.
Я составил список дел на завтра.
I compiled a to-do list for tomorrow.
In this sentence, 'составить' is used in the figurative sense of providing presence or accompaniment.
Книга составила мне компанию во время поездки.
The book kept me company during the trip.
Here, 'составить' is used to indicate forming or making up a group or entity.