You can install Premiere Pro and other Creative Cloud apps on up to two computers. If you want to install it on a third computer, you'll need to deactivate it on one of your previous machines. Learn more about activating and deactivating Creative Cloud apps.
You can download and install Premiere Pro on macOS and Windows. For detailed system requirements and hardware recommendations, see:
Editing high-resolution video can be slow. To improve performance while editing, create lower-resolution clips, called proxies. Then switch back to the original files for your final output. Learn more in this tutorial, Work offline using proxy media.
Yes. Learn how to get the most out of your DSLR videos in this tutorial, Edit DSLR video. Create slideshows and time-lapse image sequences, apply effects and transitions, and make color adjustments.