It's no problem, and thank you for clarifying.
Firstly, you haven't mentioned doing it, so make sure to install the
Patch 3 Mod Fixer. Don't look at the title, you need this file for most mods to work on the current patch. Just drop it into the Mods folder with the rest of the .pak files. You will also need to install the
Improved UI mod for Expansion to work (this one needs to be activated through the mod manager, described below).
Secondly, if you're using BG3 Mod Manager, here's how to make things work:
1. Drop the .pak files of your mods into the Mods folder.
2. In the mod manager, you have two panes: Active Mods on the left, and Inactive Mods on the right. At first, all your mods will be shown on the right. Move them to the left by drag-and-dropping them.
2.5. Some mods need a specific order to work properly. For your setup, #0 Improved UI, #1 5e Spells, and #2 Expansion should work fine. You can rearrange the mods by dragging them.
3. Save the load order. This can be done either through the ribbon menu by going File->Save Order, or by pressing Ctrl+S. When the order is saved, a green message should appear at the bottom of the manager.
4. Launch the game.
Provided all the prerequisites are installed and the mod order is saved, you should be getting the new spells and class features at character creation.