Macro Using Excel Object: Comparing Two Worksheets from Two Different Workbooks

Good afternoon everyone,

I am in a bit of a dilemma in terms of this new macro because I am working with several new ideas/concepts that I have little to no experience with. First off, my objective is to compare the data from the master worksheet with last months by highlighting any changes that occurred within the "Comments," column OR "Acct Number," column OR "Attribution Due Date" column in the current months’ worksheet.

Some situations are listed below to put the situation into context:
1) Several groups have the same project but change the due date
2) Any new rows are added
3) New teams under the "Comment" column undertake a new account number

In essence, any changes made in the three columns listed above

Additionally, is it possible to somehow keep track of new groups that are added to a seperate worksheet ("SLA Groups") that fills in the drop downs choices for the "Comments" column? I would then proceed to just highlight that new group if it was used. The designated worksheet that I am working with will always be named "Master." After those highlights are made, the rows that are marked would be copied and pasted into a new workbook. The point is so that our teams can track our changes so that our team members are able to track their project due dates and allocate their time accordingly.

My main problem lies is that I am a bit confused on how to compare two different worksheets from two different workbooks. I was advised that the best way to do this is by creating an excel object because it will automate the process and make it quicker. Also, this is a monthly worksheet so is it possible if the macro could automatically pick up the latest month file path? If anyone would be able to help me out I would greatly appreciate it.

Attached are the two workbooks I am working with. If there are any questions I would be happy to answer them.