Using GPIO on modern evaluation kits

Hi,

I'd like to to use the GPIOs on evaluation kit/ development board.

My project require connecting them back into the FPGA.

Is there a possibility to solder/connect those pins on ?

I consider using dk-dev-2agx125n (dev. board for arria ii gx),

and it is not clear how to connect to those pins.

I also would like to evaluate FPGA performance with different core voltages.

Is there elegant way to do it on evaluation boards?

Thanks :)