i need to clean up storage. how can i move all the videos and photos? to my computer? thumb drive??

Are you storing the photos on iCloud, or only on the iPhone?

You can use a thumb drive with an iPhone if you want, or you can connect the iPhone to the computer directly using its Lightning to USB charging cable, and transfer the photos directly if you want by following the steps in the support document you posted from. Transfer photos and videos from your iPhone or iPad to your Mac or PC - Apple Support

Click here ➡️ Connect external storage devices to iPhone - Apple Support