Clause 5 of ISO45001:2018 gives requirements for what top management of the company needs to do to ensure that the management system is in place and will be successful. This relates to the fact that is top management does not support the OHSMS it will be difficult to maintain if it does not fail completely. The clause starts with a list of what top management needs to demonstrate to show commitment (clause 5.1), then gives the requirements for creating the OH&S policy (clause 5.2) which provides the overall goal for the OHSMS.
Following this are the roles and responsibilities (clause 5.3) of the OHSMS which need to be assigned by top management to ensure that the system works properly, and the requirements to ensure that you have adequate worker participation in the OHSMS (clause 6.4) since workers are one of the key interested parties in the successful OHSMS.
For a better understanding of the ISO 45001:2018 standard, see this whitepaper: Clause-by-clause explanat ion of ISO 45001:2018, https://info.advisera.com/45001academy/free-download/clause-by-clause-explanation-of-iso-45001