How to connect to a Raspberry Pi in SSH?
SSH is a secure protocol in order to access to a remote machine. This is not specific to Raspberry Pis but as a Raspberry Pi is a machine, well SSH has all its senses.
In order to connect in SSH, you need to enable SSH on the machine, so to say, you need to say to the machine that it accepts to be open to the outside, you cannot do this action remotely, so you need at least once to access physically to the machine.
Once done, in order to connect in SSH, you need to type in a terminal the following command:
if the identifier, the ip address and the password which will be asked to you are correct, then you will enter within the distant machine and you will be able to control it.
Note that SSH does not provide you with a GUI (Graphical User Interface) so you will need to know the different Unix commands you need to type in order to control the Raspberry Pi. Of course at the beginning you don't know them by heart but with time you will learn them.