This is achieved by selecting a high frequency.
In order to be compatible with these mods, The Elder Scrolls Legends - Loading Screen also needs a very high priority. Most mods that replace vanilla loading screens don't technically replace them, but instead add new loading screens and give them a high priority, such that they will almost always be used. To make this mod compatible with vanilla loading screens and loading screens from these kind of mods, you need to select a frequency below 100% in the Fomod installer.
These mods add loading screens in the same way as vanilla loading screens. There are two types of loading screen mods: In general, this mod is compatible with all other mods.