Head over to https://github.com/RetroHursty69/HurstyThemes to grab the installation instructions. I wanted to add all these themes to the standard Theme Downloader in Emulation Station, but the admins of RetroPie said the list was to large for the current interface. So I had a chat with David Marti and he came up with the idea for me to have my own theme downloader. David made the script for me, which I am eternally grateful. I also came up with the suggestion of the idea that it would be cool if ES would randomly pick a theme each time it boots up. Once again David made the script happen. So the video will show you how to add it to your Pi Build (Emulation Station only). If you like to change up your themes often, then the randomizer may be the answer for you.
To add any of the EmulationStation Themes manually to your Retropie build, you will need to connect to your Pi from your Mac or Windows PC. I don't have a guide on how to do this, so I suggest googling and searching on YouTube. There are so many little variations to this process. If using a pre-made image, the maker may have changed the Pi username and password or something like that. It is best to find this information from the internet. Configuration guides are not my thing and in most cases I need help myself. The video here is from ETA Prime but there are plenty others out there too.
Adding an Attract Mode Layout (Theme) is a manual process. ETA Prime has a great video on it.
Why not make your own theme for EmulationStation? Like anything new, it seems difficult at the start. I do not understand code at all, but with help from the community I got started, then I got hooked. I made a video series to try and help people get started. The videos are lengthy and at times boring , but I hope it will help some of you understand some basics. I do not pretend to be good and an expert in this hobby, I just tried to pass on some tips I have learned along the way.