Hello again @testware73
I was informed that this guide is outdated and also that original project is maintained by community.
https://aur.archlinux.org/packages/onlyoffice-bin
With manual installation you can try adding dependencies and running the whole project again:
sudo pacman -S --needed base-devel git
git clone https://aur.archlinux.org/onlyoffice-bin.git
cd onlyoffice-bin/
// Add dependencies
sudo pacman -Syy gst-plugins-ugly gst-plugins-base-libs gst-plugins-bad-libs gst-plugins-base gst-plugins-good
makepkg -si
Please note that is by no means an official recommendation.