Hello again, thanks for answering so quickly.
In k-ubuntustudio apt is used and also snaps or flatpak
The package manager in kubuntustudio is muon, which is like synaptic and I checked that lv2-dev is installed and if I typed the command sudo whereis lv2/lv2plug.in/ns/lv2core/lv2.h I didn't get any results.
But for testing it occurred to me to create the lv2plug.in folder inside /usr/include/lv2, then inside lv2plug.in the ns folder and inside 3 other folders called ext extensions and lv2core:
/usr/include/lv2/lv2plug.in/ns/extensions/ui/ui.h
/usr/include/lv2/lv2plug.in/ns/lv2core/lv2.h
/usr/include/lv2/lv2plug.in/ns/ext/ (here copy the contents of the lv2 folder except the lv2plug.in folder)
After that if I repeat the command sudo whereis lv2/lv2plug.in/ns/lv2core/lv2.h the result is-->>lv2.h: /usr/include/lv2.h
Thus the installer that you provide to install the instruments gives the following output:
Installing the wave files. This may take a while.
/usr/bin/ld: cannot find -lnbplugin: No such file or directory
collect2: error: ld returned 1 exit status
Error compiling plugin DSP
At this point the installer stops.
Surely you are horrified that I have done something like that.
Is there a solution to the problem or should I just forget about it for now?
I know that debian is the mother of almost all linux distributions, but the truth is that a priori it is more difficult to configure as needed for audio, for example, for someone like me who is not expert enough, as a system administrator, no. I'm a computer scientist and if you don't know what you're doing it's easy to load the system.
As for the suggestion to use debian or AVLinux, I will weigh it, although I have just reinstalled my system due to changing the hard disk to SSD DRIVE and I am already finishing installing what I wanted in kuntustudio 22.04 LTS KDE plasma desktop.
I was only missing something like No Budget Orchestra Plugins, because it is something that is missing in linux, at least in the way you have developed it, there is very interesting software in windows but it doesn't quite work correctly with WINE.
I have to say that I am not a professional musician, I only have basic notions but I try to learn, and in terms of knowledge of the Linux system I have been using it for years, but at a user level, not a developer one.
I'm not afraid of using the console but on the other hand I'm not an expert so sometimes in situations like this I don't know how to solve the problem that arises.
My heartfelt thanks to the developers who directly help those of us who use their software.
My native language is not English. I am using a translator from Spanish, I say this in case the translation is strange at any time.
I do not want to take more time, thank you for your attention, regards.