Before Going To The Qc  stage , site ready ness  file upload mandtoty  how to achive this in the blue print transition 

On click of the Predelivery transition can we show site ready ness  file upload mandtoty 

or on click of the QC show the alert message  site ready ness  field up load on clik also once they filled only move to to next transition .

Pls provide some solution to achive this in Zoho crm