You will probably wish to begin by seeing the demonstration if you have not done so already. You should then look through the chapter on "Command syntax", but you will probably wish to study this properly at a later date.
To analyse your own data you will need to produce it in a suitable format (as described below) using a text editor or spreadsheet. You can then load it into EASISTAT using the DATA command and you may try out any of the other commands described in the rest of the documentation. As you become more familiar with EASISTAT you should make an effort to familiarise yourself with the use of command files, and with the more complicated arithmetic and logical operations available.