This is the default screen. To start pg_top:
pg_top [-d
Where '-d' specifies the database to connect to, '-U' specifies the database user, and '-W' will prompt for the password if a password is required to connect.
Use the 'Q' key and enter a PID once pg_top is started.
Use the 'E' key and enter a PID once pg_top is started. The 'E' commands runs 'EXPLAIN' and 'EXPLAIN ANALYZE' can be used by using the 'A' key followed by a PID.
Use the 'L' key and enter a PID once pg_top is started.
Use the 'R' key to display user table statistics. Use 't' to toggle between displaying cumulative and differential statistics.
Use the 'X' key to display user index statistics. Use 't' to toggle between displaying cumulative and differential statistics.