[Question] Cant figure out the example, opening PDFs

[LamprosPitsillos]

Tried following the example given to have nvim open pdfs in zathura instead of binary form but nothing happens,expect from nvim opening the pdf in binary.
Am I doing something incorrectly or am I completely misunderstanding how this feature of the plugin works?

require("filetype").setup({
	function_extensions = {
		["pdf"] = function()
			vim.bo.filetype = "pdf"
			-- Open in PDF viewer automatically
			vim.fn.jobstart("zathura " .. '"' .. vim.fn.expand("%") .. '"')
		end,
	},
})

Running the command from the opened buffer works fine.
:lua vim.fn.jobstart("zathura " .. '"' .. vim.fn.expand("%") .. '"')