Real programs lean on code other people wrote: a UUID generator, a
YAML parser, an AWS client. In Go you pull that code into your module
with go get, and the toolchain handles the download for you.
From inside a module (a directory with a go.mod), you name the
package by its import path:
go get github.com/google/uuid
The import path doubles as the download location. Go fetches the code, picks a released version, and wires it into your module. That is the whole step - there is no separate install command and no global list of packages to edit by hand.
Run go get <import-path> from inside a module and the dependency is
ready to import.