I want to install plank from the github repo,and added the repository but apt defaults to installing the package from the default Elementary OS ppa.(The first package)

How do I selectively install the second one ?
I want to install plank from the github repo,and added the repository but apt defaults to installing the package from the default Elementary OS ppa.(The first package)

How do I selectively install the second one ?
by specifying not only the name, but the full version:
apt install plank=0.11.89+git20211104…
You probably want to look into apt pinning to tell apt that it should prefer that specific PPA over your distro repos.
BUT: I don't know Elementary OS. I don't know whether you can just install Elementary OS packages on your Ubuntu Focal. If not, you might run into trouble.