Personas are descriptions of fictional end-users of a product. They usually involve some information about the individual's needs and frustrations, as well as some additional personal details to bring the character to life. Personas are written for all kinds of products, not just software. For example, a toaster company might produce a persona like this before designing a new appliance:
Although personas are fictional characters, they should always be based in reality. Often, developers will have a particular individual in mind - perhaps a user who had complained about a previous version of their software not doing what they wanted it to. They can also be created by first clustering data from surveys or focus groups.
Personas help developers remain conscious of the diversity of people who will use their product. As an example, consider computer operating systems like Windows and MacOS. Almost everyone in the UK uses these products, so the developers need to ensure their designs are appropriate for the entire UK population's goals and capabilities. However, operating system developers represent a small subsection of the world's population: they're tech-savvy and passionate about low-level programming. What kind of operating system do you imagine they'd produce if they didn't put themselves in other people's shoes?
In your groups, have a look at some more example personas online. Then, as a team, document at least 3 personas for your chosen opportunity using the template provided by your coach. Be ready to share these with the class and your coach.