Linux Lite doesn't make graphics drivers. AMD decided, so far, not to include their drivers in the Ubuntu 16.04 base, which is what Linux Lite 3.0 is based on. If you're staying with Linux Lite 3.0, and you have an AMD graphics card, you'll need to use the open source driver for it. If it isn't working out for you, then revert to Linux Lite version 2.6 or 2.8 for now.