Hey, @CBridegroom-1206! :)
There are a couple of different ways that you can do this. Personally, I like to create a new column on the Report tab (name it something like "Week") and then use use the "WEEKNUM" function in Excel on the date column to return a week number all the way down the new column.
NOTE: To create a new column that will show up on the pivot table, you need to insert the column between two existing ones (i.e. not at the end of the data).
From there, you can go over to the the Summary tab with the pivot table and click Data > Refresh All:

This will give you the new dataset to work with in the pivot table to get your totals out by week. And then, presumably, if you run the report on one month at a time, your totals would be the monthly totals overall.
Happy to continue to work on this here so that the whole Community can learn from this stuff, but if you are the same Carol that is one of our Fleet Nav customers with whom I'm working already on a PC report, please feel free to reach out directly via our Support email to request any help you'd like on this (that is, if you would like to work directly with your own data). I'd be more than happy to set aside some time to get you exactly what you're looking for, and we can even go into the basic Excel stuff to get you more comfortable with pivot tables and all the stuff we can do with them if you'd like. 😊
Something else I thought worth mentioning, if you (or anyone else reading this later) would like to become an Excel pro and prefer a more comprehensive self-paced training, I learned a ton of useful stuff via Chris Dutton's Excel courses on Udemy. I took his ones on advanced formulas/functions, data visualization, and data analysis with pivot tables in my spare time over the course of few weeks early last year, and it made me much more comfortable with doing the data stuff in MyGeotab. (NOTE: Those courses go on sale for between $10 and $15 regularly; I'm guessing their next sale will be around St. Patrick's Day. Also, I don't make any money recommending these, they were just really helpful, so I like to share them whenever possible.)
Hope this helps! :)
Best,
Joy