I think I've seen which charity is advertising this role and it isn't a small one. It's one of the major UK charities.
Unless you already work in risk, compliance or assurance, this is not a role that you will be able to pick up on the job. You will be required to hit the ground running.
You will be a senior leader, managing the heads of 4 teams. i would expect the day to day to consist of meetings with other senior leaders in the organisation, people management of your team, reviewing docs, policies, procedures, assurance outcomes of work undertaken by your team and providing sign off, generating plans for work for the team moving forwards, managing processes, training and undertaking L&D to keep up to date with charity commission regulations and developments, managing the outcomes of risk incidents or near misses as they occur plus plans to prevent in future.
Do you have any experience in risk, legal or assurance, OP?