so im using GTmetrix to determine the speed of my website but can't seem to figure out how to add expire headers. and where to put it?

some other things it recommends me to do is minify my css andhtml. and enable G-Zip. but i really dont want to do that.

another thing i need to do is Specify a Vary: Accept-Encoding header
i have no idea how to do that. or let alone ever heard of it.