Buy cycle shoes - rip out the hard plastic insole/insert that the cleat screws into - remove insole from your running shoes (and maybe some of the inside of the sole if possible) - cut a hole for the cleats in the sole of your running shoes - place your hard plastic insole/insert into your running shoes - put insole back over the hard plastic insole/insert.
It's really basic stuff - you may have to adapt stuff depending on numerous unknowns.
Buy cycle shoes - rip out the hard plastic insole/insert that the cleat screws into - remove insole from your running shoes (and maybe some of the inside of the sole if possible) - cut a hole for the cleats in the sole of your running shoes - place your hard plastic insole/insert into your running shoes - put insole back over the hard plastic insole/insert.
It's really basic stuff - you may have to adapt stuff depending on numerous unknowns.