Processing ALOS PALSAR in sentinel 1 toolbox

Am trying to generate interferograms in sentinel 1 toolbox using alos palsar level 1.1 data, however after stacking, am getting errors when i try to execute the interferogram formation tool

Any assistance would be highly appreciated

Interferograms can only work on complex data. You have here two intensity bands.

Thanks for the response, so how would i go about it right from two level 1.1 Alos Palsar images?

Please take a look at the Interferometry tutorials: