Preparing an Excel spreadsheet for linking (need attachments for clarification)

I am attempting to link two spreadsheet. Linking is not the issue.
Let's call spreadsheet (A) Lab Measurements. You are required to sample "Boogie Creek" for water quality. You must do this five times per month. It doesn't matter what days you sample as long as you sample 5 times. You will sample for flow, volume, pH, and turbidity. After returning to the laboratory you will calculate to find MGD(million gals/day) and (CFS per/day). All of this information will be logged on a spreadsheet under the date of sampling.

Same scenario for the other 4 days that month.

The second spreadsheet (B) is a monitoring spreadsheet including tons of data which is sent to state agencies for proof of compliance.

The reason for being able to link is of course to eliminate multiple duplicate or triplicate entries of the identical data.

OK, now the tough part. Spreadsheet A needs to link to B, however, A's data is always collected on a different date so there is no method of linking other than some type of array. Arrays are not my strong suit, but maybe with some guidance I can grasp the idea.

Thanks to all who comment. I hope someone has had a similar experience and has a simple fix. I have attached A and B spreadsheets.