The most important settings to configure for the Profit & Loss are the Date From and Date To. This specifies the period you are interested in.
If you have multiple companies, departments, or department groups, then you have the option to view a report for any of them you choose.
Show Comparative will display a comparison with the same period the previous year. So if you choose 1 Jan 2020 to 31 Jan 2020, the comparative period will be 1 Jan 2019 to 31 Jan 2019
Show Year to Date will display an extra column with the figures for the financial year to date. If your year begins on 1 April 2019, and you are viewing the period 1 Nov 2019 to 30 Nov 2019, the year to date figures will cover 1 Apr 2019 to 30 Nov 2019
If your database has budgeting enabled and configured, the Show Budget option will display the budgeted figures for the selected period. Show Budget Variance will display the difference between the actual and budget figures
Percentages will display an extra column showing the value of each figure as a percentage of the total sales. If your total sales are £100,000, and your salaries are £30,000, it will show 30%