We started reading the wiki page about creating packages first.

Read the guidelines we should follow.

Then we analyze pkgbuilds of others. And finally we copy/paste this code to make our own package.

https://aur.archlinux.org/packages/gnome-meta/

Normally these pkgbuilds follow the rules but you need to check that. That is one of the dangers of copy/paste.

We will create a new package we can now all install with

General Package Building Information

On the AUR you will find thousands of PKGBUILDS.
You can use their PKGBUILDS or make one yourself.

AUR = Arch User Repository - A user is someone like you and me.

Here are some interesting links if you want to make your own 'recipe' or PKGBUILD.