Both such beautiful cats with gorgeous faces and expressive eyes. Love the markings on the calico girlie.
I cannot add to the advice already given. It will take time. One day you will look down at your lap thinking there is only one cat there, and there will be two - that is what happened with us.
Lots of hissing and circling round each other at first, separation and gradual introduction, a bit of swatting, eventually a lightning quick nose-touch, then one day, there they were snoozing happily together on my lap. Now,they sleep together like the yin/yang sign or with their paws interlaced.