To connect to your VPS, you will need to use SSH. On Windows, you'll need to make use of a SSH client such as PuTTY, if you're on OSX, you can use the pre-installed Termial app (under applications > utilities). Those running Linux can also connect via the command line.

If you're using PuTTy, you can simply use the interface to start the connection. It will prompt you to enter the password once open.

For OSX/Linux users, simply run the following command from terminal/shell:

ssh root@<vps ip>