Do I have to create a floating layer after "rotate"?

[blogsofwardotme]

[attachment=13479][attachment=13479][attachment=13479][attachment=13479]
[attachment=13479]
On the second layer, first screenshot, after rotating the element with my mac pad, I clicked "rotate" in the tool window, just to see what happened. That created a floating layer, I don't know if I am really supposed to click on "rotate", after doing it manually.
Basically, what I need to do is removing the excess mask from my element, but the mask on the second layer is no longer active after creating the floating layer.  Is Gimp trying to tell me that I should create a new mask on the floating layer?
The screenshots order is inverted.
Do I necessarily need the floating layer after rotating? thank you

[rich2005]

I have read your description and still do not know where the floating transformation layer comes in. If you have a floating layer, usually two options - anchor it or promote to a new layer.

I assume you are making a "Glow" around the fist. It might go like this:
Click on the layer icon
Move / (scale if required) / rotate - I used Rotate but Unified Transform does all in one tool.
Click on the layer mask icon and adjust the mask.
30 seconds example: https://i.imgur.com/invovaX.mp4