All of the theme designs listed on ThemeFlood require RapidWeaver 5 or later. Themes get downloaded as
.zipfiles, to your computer. You can safely install new theme designs by double-clicking on them, to extract the zip package. Double-click or drag and drop the
.rwthemefile onto your RapidWeaver dock icon, to install the new themes. Once installed, you can open the themes drawer in RapidWeaver to select a theme design and apply it to your project. If you want to learn more about ThemeFlood themes, the knowledgebase is well-worth exploring.