Here is a way to create instructions that can be re-used in quizzes many times. Using this method means you are also able to update the instructions in one location in Canvas and have them updated automatically in any quiz that uses those instructions. This is also useful if you're creating quizzes but haven't quite decided on the best wording for instructions yet. You can insert the instructions now, then come back and edit the instruction bank later and have it update through all of your quizzes.
1) First, create a question bank in a sandbox course. Title that question bank with the title of your instructions. I start my instructions with an underscore so I can recognize them right away.
2) Create ONE question in that bank of the type "text (no question)". Edit the question, entering your instructions how you would like them to look.
3) In any quiz in which you want to place the instructions, add a question group. In that question group, select 1 question worth 0 (zero) points. LINK the question group to the bank you created above. Once you add the group, you can drag it to where you want it in the quiz.
4) You're done. If you ever want to edit the instructions, just go back to your question bank and edit that question. It will be updated in any quiz that links to those instructions.
I often have similar quizzes with groups of questions organized like this:
"The following intervals are Ascending Melodic intervals. Label the interval and select the correct note using SPN"
[Questions 1 through 5]
"The follow intervals are Descending Melodic intervals. Label the interval and select the correct note using SPN"
[Questions 6 through 10]
"The following intervals are Harmonic Intervals. Remember that the given note is the bottom note. Label the interval and select the upper note using SPN."
[Questions 11 through 15]
"The following intervals are cumulative. This can include any intervals you have practiced up to this point. Remember that for harmonic intervals, the given note is the bottom note. Label the interval and select the upper note using SPN."
[Questions 16 through 25.]
So in my question banks I have 4 banks with the following titles:
I add them to every interval quiz and drag them to the appropriate location in the quiz. If I ever want to change the wording or add more instruction, I just edit the question banks.