This does sound like a fuse.
But you mention the cardboard and the possibility of dislodging something. So if the fuse is good, you'll need to keep investigating.
If the fuse panel is under the hood, the cardboard scenario would only be a coincidence...unless somehow you caused a short circuit by pushing the cardboard around under the dash. Anything's possible, but that seems unlikely. It's more likely that you disconnected something.
One possibility is the "flasher." Signals blink because of a device called a flasher. You can hear the clicking of the relay, which suggests the flasher is under the dash. (I don't know why the cameras are also dead unless they only work when you activate your turn signal.)
A dislodged flasher or flasher connector could be the culprit. These are typically a relay-like device. Here's what it might look like:
https://www.summitracing.com/parts/m...Fc-1wAodRPUIjw
This may not be the correct flasher if it also activates the side view cameras, but yours would generally look like the illustration.
The mounting lug on the flasher (illustration) suggests it may be mounted to a panel with a screw, and a small wiring harness with a push on connector might connect to it, but the flasher might just plug into a socket up under the dash, and the lug might be missing from the factory flasher (the lugs are removable).
Information like fuse and flasher location is available in your owner's manual. So, when out of range of this forum, it would be a good idea to be familiar with the layout of your owner's manual. Most of it is reference material and does not warrant reading in advance, but things like electrical circuitry, lubricant types, tire pressures, and many more details are typically available in charts and tables at the back of the manual. The manual should be indexed. If you need to change the flasher, I suspect the part number will be in the manual as well as imprinted on the flasher itself.
Another consideration. If you blew a fuse, the next question is why? Fuses typically blow only if there is too much current - usually from a short circuit of some sort or a significantly overloaded circuit. If you haven't customized the turn signal system in some way, it's likely a blown fuse indicates there's a short somewhere. It's pretty rare for a fuse to just give up the ghost and blow out.