Very first time downloaded docker-1.12.2.tgz, as root on redhat7, what to do next?

notice my linux do not allow download from docker.org and no yum install docker-engine,
so i assume this tgz file contains everything.

what do i do to start docker? (tried many ways and read many wiki, but still non of them works)

Thank you

Jack

fig it out. now need address the deviceMapper