Source code installs are the same as for any other PostgreSQL extension built using PGXS. Make sure the directory containing pg_config from the PostgreSQL release is listed in your PATH environment variable. You might have to install a -dev or -devel package for your PostgreSQL release from your package manager if you don’t have pg_config. Then run make USE_PGXS=1 to compile, and make USE_PGXS=1 install to install. You might need to use sudo for the install step. e.g. for a typical RHEL 7 install, assuming you’re using the yum.postgresql.org packages for PostgreSQL:
sudo dnf install postgresql96-devel ; sudo PATH=/usr/pgsql-9.6/bin:$PATH make USE_PGXS=1 clean all ; sudo PATH=/usr/pgsql-9.6/bin:$PATH make USE_PGXS=1 install
Note that you must install pglogical on all servers that will act as publishers or subscribers. So if you’re replicating from 9.4 to 9.5 you’d install postgresql94-pglogical on the 9.4 server and postgresql95-pglogical on the 9.5 server.
For more information, please read the pglogical README.md in /usr/share/doc/postgresql-pglogical/README.md where would be 94,95,96,10,11, 12