This is the 11158th most frequent Russian word.
готовыми
"Ready" or "prepared" (plural instrumental form).
In this sentence, 'готовыми' is used as an adjective in the instrumental plural form to describe the state of 'мы' (we) as being prepared.
Мы пришли на занятие уже готовыми.
We arrived at the lesson already prepared.
Here, 'готовыми' functions as a complement to the direct object 'их' (them), indicating their readiness for challenges in the instrumental plural form.
Я всегда считал их готовыми к трудностям.
I always considered them ready for hardships.
In this usage, 'готовыми' serves as a predicate that describes 'нас' (us), to show our qualification for being participants in the instrumental plural form.