Integration of ISO 9001:2015 into the Internal Audit Schedule

Hi all. The company I work for has HACCP and ISO 9001:2015 certification. I am in the process of updating the Internal Audit Schedule and am stuck on how to integrate ISO requirements into it. Some PRP's from HACCP are included in the ISO standard. For the remaining requirements, I am wanting some advice on whether others are members are completing an internal audit checklist of the standard in its entirety at once, or completing a section of the standard each month? Also, previously the internal audit of the ISO standard on site was to examine the procedures for each Department to ensure they are correct. Is this something that others are doing? Thank you!

I simply link related ISO9001 clause(s) to each audit question. For example: production records => 7.5.3, 8.5; site observation => 7.1.3, 7.1.4; cleaning activities => 7.1.4, 8.5.1; training records => 7.2, 7.3; training materials => 7.1.6; supplier evaluation => 8.4; HACCP => 6.1; QC files => 8.6; customer complaint treatment => 5.1.2. 8.7; recall rehearsal => 8.5.2, 8.5.5, 8.7; etc.

After that I rescan to check if any clauses are missing.