Download the pack from the link above (game itself is not included). G-Drive and One-Drive may require sign in if the limit per day gets used up. I added a Dropbox link as a back up if that happens.
Unzip the archive and you will see Flycast exe (Emulator FAQ), the mappings and data folders. This version of Flycast is meant for Windows PC, but there are builds covering several platforms (Android, Linux, Mac, iOS, Switch, Xbox) available at the builds page.
If you plan to use the Boxart option instead of a simple list, you can add your own boxart or fetch it automatically. Afterwards, you can edit the .json file in the boxart folder and add the correct paths to your box art.
Go to Data > Skins > Button Layout and choose a UI texture sheet depending on the type of controller you are using and paste it into the game's texture folder (PlayStation layout is the default one). You can also choose a different style of cowl and two types of look for the Sarafan Tomb (retail or alpha, see the comparison here).
Launch Flycast and click on settings, go through each page, add the correct paths to where your game is located. I added mappings for most of the modern controllers, but in case your controller is not recognised, you can map the buttons yourself. Make sure you map down or up on d-pad to the Select button and d-pad left and right need to be mapped to the triggers.
The most important setting is the Video tab. Make sure the "Load custom textures" field is ticked if you want to see the new textures. Widescreen cheats only work on PAL version, so keep that in mind, otherwise it is best to play in the original 4:3 ratio to avoid any glitches with the HUD and the wraithblade. This mod should work in RetroArch as well and other devices which can run the Flycast emulator. Also make sure that the DSP is ticked in the sound settings, so the audio does not cut out.
Flycast video settings screenshot example: