GarageBand Sampler acting glitchy and not functioning for me?

I've recently installed GarageBand (v. 10.3.2) and I'm attempting to create a custom drum kit using the AU-Sampler. It seems very intuitive and just what I'm looking for, though it's acting very glitchy for me... to the point of useable.

I'm following a youtube tutorial on the process but I'm encountering countless glitch type problems as I go along. I'm attempting to assigning each individual WAV sample to one key - with a key range and root note range of 1 key or note (similar to a standard keyboard's drum kit sound bank). I'm following this tutorial: https://www.youtube.com/watch?v=ACxbcQobFXY

I'm importing all of the WAV drum samples (approx. 20) into Layer 1 and then deleting the Sine 440 built in piano. The problems start when I'm importing. The WAV samples under Layer 1 only partially show up though they're there. I have to click on them and then click on another sample that the name is showing, then the previous one will appear. The little check marks are there, but there's no file name.

Then, when I'm assigning an individual sample to a note, the parameters don't respond... like, where you enter in the key range and root. When I enter one or the other, then TAB to move to the next, it doesn't jump to the next box. It doesn't matter if I TAB or manually click in the next box... it simply gets glitchy. The text in the velocity level space (above the keyboard) get's all jumbled and hieroglyph looking. It's hard to explain, but following a tutorial step by step, my Sampler is not responding and encountering glitch-like limitations unlike the tutorial. It's literally not useable.

Is there any known glitches or fixes for this issue? I couldn't find any ref. to any online.

Is this one of those "uninstall / reinstall GarageBand" kinda deals... or is there some sort of directory / cache kind of files to clean or remove for example?

Thanks! Chris