Hi Grace,
from your description it is hard to understand the concrete issue (a screenshot would help).
I try with my reference system to explain some issues.
1. you are not the responsible person:
When I am not the processor of the task, all actions are greyed out.
2. prerequistes are not fulfilled:
there is a button to display prerequistes.
Please check and provide a screenshot with more details, if this does not help.
Best regards
Marlene