go get command downloads and installs packages in your go workspace, as denoted by the
GOPATH environment variable. You must set this first for Atom to be able to download utilities.
You may use the
go env command to verify, also you can click on the
go-plus icon at the bottom of Atom to see the
GOPATH value visible to Atom.
Your screenshots and comments indicate you have an invalid folder value in your
GOPATH. Easiest is to set it to a single, absolute folder. You can read more about it here: