There are a few ways to get your photos on your computer.
A) If you have a Mac and iCloud photo sync enabled they should automatically appear within the Photos app. However, it can be tricky to extract the RAW file. For the full details, check out Apple's Knowledge Base Article.
B) If you tap the "Share" button in the photo reviewer, it will ask if you want to export a JPEG or RAW. You can then AirDrop it to a Mac or other iOS device. This can take a while if you go one-by-one.
C) If you plug in your iPhone to a computer it should show up as a normal camera. From there you can import it via the Image Capture utility on the Mac, or the Photos utility on a PC. You could also use a desktop photo syncing app like Lightroom.