You asked "How do i put in place clauses 4.1.5 and 5.4 in the laboratory?"
To meet clause 4.1.5 requirements, a laboratory must use various operational activities such as audits, feedback from clients, evaluation of contracts and providers of services and products to identify risks to impartiality. Action must be taken to minimise or eliminate the identified risk, typically through a change in the process. For more information, see my response to a question Preparing risk analysis with regard to impartiality and confidentiality, at https://community.advisera.com/topic/preparing-risk-analysis-with-regard-to-impartiality-and-confidentiality
Clause 5.4 has to parts to the requirement. Firstly a laboratory must implement a system that ensures all client contractual obligations, legal obligations (e.g labour laws and occupational safety, health and environment laws) are met. Then depending on the sector, the requirements of the IS7025 accreditation body, any certification body, and any other association, for example a professional body must also be met and maintained.
The second part of the clause states that if a laboratory performs activities away from the main registered location, e.g in the filed or at a clients premises, it is the laboratory’s responsibility to make sure these requirements are still met.