Customer performance indicators is referring to your management of customer complaints. Typically you will log customer complaints and do trend analyses on them frequently to identify target areas for improvement or other issues.
Resource requirements is referring to things that are provided in support of your food safety system (adequate personnel, training, funding, etc.).
They want to see that you've reviewed all of the subjects above with management, as management is typically the group to approve spending for things such as equipment upgrades, increased training programs, etc. It shows that communication is strong throughout the organization and that management is aware of issues and is in full support of the food safety system.
To cover "at appropriate planned intervals" you will want to create a procedure for this that states when everything will be reviewed (annually, semi-annually, etc.). Our SQF auditor wanted to see that a list was created to ensure that no review items were ever missed so that in the event I'm not able to be there that every item can still be reviewed as required. I created a checklist as a controlled document that lists everything required for review during the management review meeting (so that anyone could basically pick it up and know what needs to be covered), which I include with the meeting minutes.
I keep meeting minutes that I have everyone sign off on and I keep on file as proof for the auditor. I will also keep copies of things such as the current documentation register, audit reports, etc. with the minutes to show what was actually reviewed during the meeting. For documentation, depending on the auditor, they may not be satisfied with just the documentation register with the minutes, you may have to actually list for every document that it was reviewed and okay'd during the management review (as proof that every document in the register was reviewed and wasn't skipped or missed).
The opportunities for improvement are important as well - they want to see continuous improvement within your organization, so during the review meeting you should identify opportunities for improvement (typically SMART objectives) that can be reviewed during next year's meeting.