I'm going to assume it's a laptop, since you want to remove the CD-ROM.
As @Someone Somewhere already mentioned you can simply remove the CD-ROM and put the SSD with a specific caddy there.
I believe those are available everywhere, you can simply google them.
The HDD/SSD and the CD-ROM all are connected via SATA, so the only concern you should have is if your laptop can hold the extra storage. What is the model of your computer?
Here's a detailed review and tutorial how to do this on a laptop step by step: http://www.tomshardware.com/reviews/ssd-laptop-upgrade-optical-bay,3102.html
I'm going to assume it's a laptop, since you want to remove the CD-ROM.
As @Someone Somewhere already mentioned you can simply remove the CD-ROM and put the SSD with a specific caddy there.
I believe those are available everywhere, you can simply google them.
The HDD/SSD and the CD-ROM all are connected via SATA, so the only concern you should have is if your laptop can hold the extra storage. What is the model of your computer?
Here's a detailed review and tutorial how to do this on a laptop step by step: http://www.tomshardware.com/reviews/ssd-laptop-upgrade-optical-bay,3102.html