Hi Shweta_sawant,
Have you input any Signal Activity Data? If you didn't input the Simulation results etc, the power analyzer does not know the toggle rate, therefore saying confidence level is low.
Please check the "1.4.2 Sources for Signal Activity Data" Chapter in Intel® Quartus® Prime Standard Edition User Guide: Power Analysis and Optimization: https://www.intel.com/content/www/us/en/docs/programmable/683506/18-1/sources-for-signal-activity-data.html
If you do not require a estimation result with a very high accuracy, you may simply use EPE tool to estimate the power consumption.
Since you already have a project in Quartus ,you can export the EPE file (<revision name> _early_pwr.csv) generated by the Intel® Quartus® Prime software and import it to the EPE spreadsheet to check the estimation result.
The EPE tool and UG can be downloaded from this page:
https://www.intel.com/content/www/us/en/support/programmable/support-resources/power/pow-powerplay.html?wapkw=Power%20Analyzer
Best Regard,
Xiaoyan