Question about Biological Signals

I watched some tutorial videos and I want to make sure I'm doing this right. Because I wasted a lot of time looking for stuff.

Basically you pull up the solar system map, look for planets with an atmo that you can land on. Do a DSS of the planet. Study the color of the "heatmap" (this is where I got confused), and try to aim for the light blue next to the dark blue? One video said a lot of the sources are near the bases of "mountains" or big rocks.

(Quick question: how do I "cycle" through the various "things" to look at on the heat map? At the top of the heat map, I remember a video that cycled through the things you can filter out or focus on… What keybind is that? Is it prebuilt in? I can't figure that out.)

Next, you get really, really close to the surface in your ship and literally use your real eyeballs to scan the ground around you while fly over the surface, as close as you can get to the ground without bottoming out? Just keep doing this until you see something on the ground that looks odd?

I spent almost three hours hopping around from planet to planet. Finally I found a few "puddles" of bacteria, scanned three different locations of bacteria growth, and obtained one sample of said bio. All of that for one sample?

I have GOT to be doing something wrong. How are you guys finding these giant xeno plants and forrests and stuff????? Sheer luck? Or is everyone going to the same places over and over again?