1- copy file to a bootable USB memeory ( using win32 ) and srx1500 .img file
2- reboot and press " ESC " and follow the instruction to "install junos"
3- reboot second time automatically
https://kb.juniper.net/InfoCenter/index?page=content&id=KB27369
https://kb.juniper.net/InfoCenter/index?page=content&id=KB30944&act=login