You have somewhere you need to be. You have to set cover and the person covering is not a subject specialist. This is a familiar story where business is a small optional subject and there is only one teacher in the school. Anyone who covers is not going to be a specialist, so here are some tips to help you write a successful cover lesson.
a) Make sure it is easy to give out, so write in the format of a one-page PDF that can be quickly photocopied. Even better if you write about ten lessons and keep 30 already photocopied in a folder in your desk drawer. Keep some good examples from previous years to distribute as WAGOLL and WILFs.
b) Write it so it is easy to read through and explain, so scenario worksheets work well as this can be read through as a class at the start. This settles everyone in the class down, indicates that work is expected and sets the scene. Questions can be asked and points clarified. The teacher can quickly establish control and those students expecting a cover lesson consisting of climbing out the window or watching a football match on their phone can be disappointed.
c) Start with some easy and interesting tasks such as designing a logo. This gets everyone on board and a drawing task is less odious than "let us all write a very long essay"
d) Chunked activity so that all students can complete tasks and feel a sense of accomplishment. This leads to motivation and happy students. Or a cycle of joy as I call it.
e) Include extension tasks for those students wanting some stretch and challenge from the task
f) Focus on a topic that consolidates or retrieves previously learnt tasks.
g) Timeless (don't put the date on or use current affairs) and you can use them year after year.
This makes writing cover lessons tricky as it needs to contain all these elements to be successful. Too much and you lose the group and chaos ensues, too little and after 10 minutes they are all asking for more work or "what do we do now" or "can we just go on our phones".
Last tip, DO NOT put the words 'cover work' or 'cover sheet' anywhere on the page as this instantly devalues it in the eyes of the student and makes the cover lesson harder for your superstar that has stepped in to take your class.
I have a couple of free ones to download on this page as examples: https://www.revisionstation.co.uk/free-cover-lessons
I hope that has helped