Welcome!
So that I didn't have to read the whole tutorial, I tried searching for "Flood" which is not found on that page. So something must be "off" somewhere. Or maybe flood is a translation which misses the mark? Also I'm trying to figure out what "Flood" is at the bottom of, that you can't bring to the top.
Oh! Unless you mean you named a layer "Flood"? In the Layers dialog, which I see is open from the images in the tutorial, there are a series of 4 green buttons: Move to top, Move up one step, Move down one step, and Move to bottom. So that way, you can arrange the layers.
Because I can think of so many different situations where you might want to do what you describe (with the 2 glow effects), I hesitate to write you some steps to reach your goal. Generally, a blur is used to create a glow effect. You can get access to blurring at the bottom of Object menu > Fill and Stroke. Basically you need to either draw a shape which will become the glow, and blur it; or you can duplicate your object and move it behind and down (or up) and blur that. Or it might be possible to use a filter.
But if you can show us what you're doing (or show an example) we can tell you more clearly how to do it. Or, you could download the SVG which Lazur attached, and study how he did it.