I'm trying to install PyGObject, so (I guess) I need to install jhbuild. I was following the tutorial that I found on https://developer.gnome.org/jhbuild/unstable/getting-started.html.pt_BR (I got there following the links on Python documentation, so it's probably the official installation guide)
I created a folder called jhbuild inside my user, and a folder called checkout, inside the folder jhbuild, and started a git bash there.
I ran cd jhbuild, ./autogen.sh
Then the message `make' is required to configure & build jhbuild
I continued the tutorial anyway with make, but the message bash: make: command not found appeared
What do I have to do to continuing the installation?
The error bash: make: command not found indicates you don't have make on your system or in your PATH.
You should install make on your system. How depends on your operating system.
It has nothing to do with jhbuild per se.
In fact I'm building PyGobject in my MSYS2+MinGW-w64 environment completely without jhbuild, using meson and ninja.
If you're a beginner and you're on Windows the easiest way to get PyGObject is to use MSYS2 and install the mingw-w64-x86_64-python-gobject package (with pacman -S mingw-w64-x86_64-python-gobject).