You're gonna need a scanner, software for that scanner and image editing software. I use the scanner that is built in to my printer, so it doesn't need to be fancy. I only scan in the pictures at 600 DPI resolution anyway. If you're on Windows or Mac I'd recommend just sticking with the manufacturer's stock scanning software. I'm using Linux and I would recommend Skanlite for any other Linux users. Image editing software is up to your preference. Photoshop is the usual go-to, but I use and would recommend GIMP which is free and available on Windows, Mac and Linux. Paint.NET is another free alternative available for Windows.

Wipe down your photos with a dry cloth. This gets rid of any fingerprints and dust or any other stains. Make sure that you wipe your scanner as well, as dust and hair can easily find its way in and mess up the image during scanning. Line up your photos to make sure they're not crooked. Don't overcrowd the scanner, I only scan in about three or four photos at a time. There's going to be some blank space and that's fine; we're cropping the pictures out anyway.

With whatever scan software you use, ensure that the entire surface is being scanned. Set the scan resolution to 600 DPI. You could go higher than 600 but with instant film it won't make a difference in terms of sharpness. If the scan comes out with smudges, wipe the images and scanner and try again. If it is crooked you could re align the photos and scan again or just fix it in editing. Save the scan to your preferred file format (I use JPEG) and open it in an image editor.

Using the image editor of your choice, crop out the images. In GIMP, drag a rectangle selection over the image and click Image > Crop to Selection. Once you're happy, edit the saturation settings. While I don't like to digitally edit analog photos, scanners tend to desaturate the image. Because of this I like to digitally increase the saturation to make it more accurate to the physical photo. In GIMP I set the saturation to +20 under Colors > Hue-Saturation and this restores the faded colors without making it inaccurate to the real photo. Finally, export the cropped and color corrected image (I use JPEG), and you're done!

I don't edit my photos besides this saturation fix, as I want to preserve the vintage look of instant film as much as I can. Feel free to edit the photos as you wish. Editing the exposure and highlighting the shadows can really make the image pop even more.