ISSUE with Switch

There is no SWITCH() function in Power Query. All Power Query functions have the type and function name with a period, so Text.Start(), Number.From(), DateTime.Date(), etc. 

SWITCH is DAX only. In Power Query, you'd need to use nested if/then/else statements, or use a custom function that does SWITCH functionality, but I would advise against that unless you are pretty good in Power Query.

If you can share what you are tryting to do, we can assist getting you started with if/then/else.

EDIT: Saw your sample logic. Try something like this:

= if [Job Role] = "Director" then 1
else if [Job Role] = "Grower" then 1
else if [Job Role] = "Manager" then 1
else null

or this if you have a default you want to use beside a null value.

if [Job Role] = "Director" then 1
else if [Job Role] = "Grower" then 1
else if [Job Role] = "Manager" then 1
else 2