The first field above you can access all Site participants but not the trades. In the second table you can choose the trades and enter the number of Employees.
To do this select a company that was present on the site. Then you can enter the daily task making a brief note of the current job these companies are working on. Then click on the next field to the right and add the number of people who were on the site. Now you only have to categorize these people according to their qualifications.
As soon as you have entered the number of workers the number of people will be calculated.