The Calculate Tab is where you will select your calculation method for your trades. You can select a method per coin, or the same method for all coins.
The available calculation methods, as well as the default calculation method, will depend on your country of origin.
Please note: There is currently no clear indication about the viability of using different calculation methods throughout the years. Some tax pros have suggested the safest way to calculate your cryptocurrency taxes is to use FIFO throughout the years. However, you should consult with your tax professional if you are unsure which method to use.