By default you are going to have to specify the entire safecoin path when running safecoin commands as such:
~/Safecoin/target/release/safecoin validators
It can be arduous to do this every time, so as a short cut, I add a symbolic link to the local bin folder:
sudo ln -sf ~/Safecoin/target/release/safecoin /usr/local/bin/safecoin
Now, to run any safecoin command it’s as simple as:
safecoin validators
This is all down to personal preference but it is something I find convenient.