Jumpy screen and how to set up a dvd / cd drive

Newbie here. I have KDE plasma running on Debian 13. Major vocabulary problem, not knowing what to call things. The desktop is bigger than the monitor screen, but it slides around when I move the mouse, so I can get to all the corners. Rather dizzying at times. Would like to be able to freeze it when working on a small window, and then release it to slide around again when desired. Is that possible?? And if so, how?
2nd question is about my dvd / cd drive that is hooked up by usb cable. There must be a procedure to set it up for use with VLC or other utility, using the menus, the unit has power, but without the software connection it’s inert. Some guidance? I appreciate any help.

The desktop is bigger than the monitor screen, but it slides around when I move the mouse, so I can get to all the corners. Rather dizzying at times.

most likely it’s that you’ve accidentally enabled the zoom accessibility feature. Meta + Ctrl and scroll to control it, scroll all the way back and you’ll have the desktop display normally. you probably do not need this feature unless visually impaired.

Thank-you Hsza ! That works beautifully. I am somewhat visually impaired, and the feature helps. Now I can use it ad lib.