No, they must act within the law. The Management Scheme contains 'Terms of Reference' which list what committees can do and 'Standing Orders' which control how they do it. Each committee controls part of the Council's services and staff. Committee meetings receive an agenda with reports from officers. These reports allow councillors to discuss policy and spending proposals and to make decisions.
Voting settles any disagreement.
At the meeting, an officer from the Council's Committee and Members' Services will take a record of the decisions. This officer will write up the decisions after the meeting into a document called a set of minutes. This document is open to public inspection at libraries, etc. The Council decides the size of committees and sub-committees and who will be appointed as the chairman of each. The Council then appoints members to each committee and, in the same way, committees appoint members to their sub-committee .