Hi Rakesh,
The EVM generates the analog and digital supply rails for the ADC using the main power rails on the J4 header. Section 5.2 of the User's Guide explains the supply rails that are available and how to configure the jumpers correctly.
Without an ECG simulator, you can still evaluate the ADS1298 performance with a function generator. The only problem I see is inputting signals as small as 1mV - 3mV. Still, I would use a function generator to input +/- 100mV signals between 0.5Hz and 150Hz and practice setting the right common-mode, gain, and ECG-specific feature settings for the device.
The ECG tab will take the data collected from each channel and perform some basic arithmetic to calculate the standard ECG Leads (i.e. Lead III = Lead II - Lead I). It will not tell you any "diagnostic" information.
Best Regards,