Spectral Creation is a small modpack consisting of Create, Spectrum, and a handful of tiny content mods, performance mods and QOL mods. Beyond that, there is a small custom guidebook that’s kind of rough to use due to poorly formatted entries. The few mods in the pack are surprisingly buggy, like Scout and ExtendedDrawersAddon (all related bugs to which are fixed in the 1.21.1 version). It can be a genuine bother, and why I would say this is probably not the ideal way to experience Spectrum, much less Create, and also probably not that suitable for building your own Spectrum focused pack off of.