The easiest way: first, install rust and cargo, either through your distribution, or thorough rustup if your distribution doesn't have it yet. Then run "cargo install -f ripgrep". It'll download the source code, build, and install to ~/.cargo/bin, which rustup adds to $PATH for you by default.

Edit: the "-f" in the "cargo install" command is for updating; without the -f, it refuses to install over an already installed version. The first time you install, you can omit the -f.