Connecting to your Linux server via SSH is usually done via Putty at https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Once you open it, you will get to enter the following fields:

Host name (or IP address)
The domain or IP you want to connect to

Port
The port of the server used for SSH (default is 22)

Connection Type
Select SSH fron the radio boxes

You can also save the session, in order to save the IP and port to connect to as a shortcut.

After you open it, you will first be required to accept the server host key.

Once done, you will be prompted to enter the username (root would be the username for the main user).

The password will be the next one, but the cursor will not move when entering it, this being a security feature of Putty.

After hitting Enter, you will be logged in and can start typing commands.