How do you modify chart schedules?

[teaching2]

Please forgive me if this is totally obvious, but my brain seems to be on vacation somewhere without me this week.  How do I download the 36 week chart schedules in a way that I can modify them? For example, moving things around or adding check boxes.

I download the PDF chart to the Notability app (this cost about $5 when I bought it a few years ago).  Any book that I won't be using is "written over" with the thick "pencil" option in  white.  I write in any subs in the now blank white space with the thin "pencil" option in black.  When a reading is complete, I mark over the box for that week with a colored dot using the highlighter option.  I also use the pencil to write in the specific composer, artist, hymns, math program lesson numbers, and any other weekly/daily subject info in the appropriate line one the 2nd page of each term's PDF page.  I then print a copy for my children's reference.  They mark off each week's completed assignments and I save it in their records.