github or una apps store, but I saw that the app store doesn't work directly from the old sites, you have to download them manually and install them manually. All the modules you have to do download and install manualy. I don't remember which version of una core the app store works from, but I saw that it doesn't work in older versions. Most PHP sites use composer, I don't know why UNACMS doesn't use it, it would be much simpler. And documentation is almost non-existent. so you have to search the forum.

you can't claim that the latest version will work with version 12, look for a specific version for version 12. https://unacms.com/download-product/developer there are different versions starting from version 9.0.0