Just to add another idea of how to put together a study timetable, I made one for DS on a spreadsheet.
First I listed out all the subjects and then within each subject, I took the topic breakdown from the revision guides, and next to each entry, Ds made an estimate of how much time he would need to revise it.
Then it all got added up, subject by subject into:
time required
time done
time outstanding
DS updates this every day with his progress.
After that, the time still needed got summarised in a table, and the number of required 45 minute revision sessions were calculated, per subject.
Finally the revision sessions were put into slots on a calendar in another tab of the spreadsheet. I used conditional formatting to colour them in. These are counted to make sure that DS has sufficient time, according to the estimates.
He's currently due to finish revising 10 days before the first exam. He won't, of course, but this way he's building in time for finding that something needs more time than estimated, or being ill for a few days.
I've been using spreadsheets for work since 1991, so i know my way around them. But this was still a big body of work (bigger than I originally thought, tbh). I'm consoling myself that it can be used for Ds2 in a couple of years time.