What would be the easiest way to make a spreadsheet collecting all context sentences?

Read about [userscripts] on wikipedia and [here] on Wanikani.
Get [TamperMonkey] script host for your browser.
Read about and install [Open Framework].
Open your browser’s Javascript console while on Wanikani (press F12, and click on the Console tab).
Paste the code from [the thread I linked above] into your Javascript console.
Then type context_sentences into the console, and press enter, and it will return a list of all the context sentences… though not in a format that’s super easy to cut and paste all at once.