My database is not installed with parallel option. Do you think I need to enable this ? If yes, please let me know how.

Then, now we are having issues with performance. The marketing team who are running the reports seem to complain that their queries are taking a long time. still havent reached the point to make out which tables are being accessed . I've just joined newly and the rest of the people who was managing all this seems to be on leave and I have nowhere to turn to.
For this system, we do a daily dataload during the early morning hours and then throughout the day, the other staff query this database to generate reports.
Could you please advice me on which paameters I need to pay attention.

thanks