Formula for outputting tasks with the Focus checkbox

I have a table with tasks and checkbox column, where i mark up focus task. I want to output this task in canvas with formula. I tried this:
switchIf ([My backlog]. [🔥] = true, [My backlog]. [Task])
But it dosnt work:(


By the way, where i can find tutorials for coda formulas, except official coda tutorials?

[My backlog] .Filter ([🔥] = true)

I found answer:)