Hi,
Before the notebook on "Assemble States", there is a notebook in section 11 unit 3 titled "Get Last N Time Bars" where we have discussed how to resample existing 1-minute data to different intervals.
First, you are starting off with 5-minute data. and for that the width is taken as 9 days, i.e. we first define the width(time interval, in days) for the 5 minutes as 9 days.
For width of 1 hour time bars, we will multiply the lookback period by 15 in order to create a time interval(width) wider than the lookback period and divide it by 24 as there are 24 hours in a day. Finally, we will apply ceil method on that (You can refer to the notebook on why this function is used). This is done to make sure that the width should be greater than the lookback period and that's why we multiply lookback period with an arbitrarily chosen number(15) higher than the lookback period.
For width of 1 day time bars, we will multiply the lookback period by 15 (to have a wider time interval than lookback period) and apply ceil method on that.
I hope this helps.