Hello @BRUCE LEE
My Concept is not bullet proof for production, i just setup a lab to test nodebb for our company it is NOT secure, but here you go! I used ubuntu server 16.04 LTS and followed installation steps from github repo of nodebb till i was able to login to nodebb.
Over npm just install "npm install nodebb-plugin-solr", now you need solr, solr comes from apache, you need java and tomcat + solr.
ubuntu have a preconfigured tomcat solr in their repo.
sudo apt-get -y install openjdk-8-jdk
ln -s /usr/lib/jvm/java-8-openjdk-amd64 /usr/java/default
sudo apt-get -y install solr-tomcat
now you can access solr over ttp://YOUR_IP:8080/solr
after that configure nodebb plugin solr like this
Save it, i think you have to restart nodebb under admin panel many times to see it work.
At the beginning the indexing is not active, you must enable it, always look on the right side for yellow marked things from my picture:
Also watch on dashboard for notices, it helps:
Good Luck my Friend!