I put all the file in my hosting server public_html.but not working.
That's not how this works. That's not how any of this works.
NodeBB, like any enterprise application, is a bit complicated. This is not a static page that you are trying to host. What you did @ALiveVam wouldn't even work for a static set of pages, let alone a dynamic application. You are lacking a viable web server (IIS and Windows aren't going to cut it here, at least not in any reasonable way, and they'd be crazy to use no matter what), you don't have the NodeJS platform involved, you don't have a database, you haven't configured the application, etc. Lots of missing parts, all of them, in fact.
I don't normally jump to this, but the number of basics being missed here tells us that you will need to hire someone to run your hosting for you. This doesn't have to be expensive if your needs are quite basic, but you do need an IT team who understands applications, databases, web servers, etc. Running something like NodeBB isn't hard, but is much harder than running something like WordPress, which is also a dramatic number of steps past where you are.
Recently I delete my PHPBB forum and decide to use nodebb. but after download, I upload all the nodebb files to my hosting server. after upload when I go to example.nodebb/forum I see a blank page.
@ALiveVam said in Need help about Install:
Recently I delete my PHPBB forum and decide to use nodebb. but after download, I upload all the nodebb files to my hosting server. after upload when I go to example.nodebb/forum I see a blank page.
Yes, we understood that. That is in no way how something like this can work. Hence my comment.
@ALiveVam said in Need help about Install:
put all the file in my hosting server public_html.but not working
I don't want to install nodebb to localhost I wand to install to my premium hosting. but how
Is the installation process different from PHPBB? i want to install nodebb at this night. please tell me about installation process.
i already finished reading nodebb documentation.
@ALiveVam said in Need help about Install:
I upload all the nodebb files to my hosting server.
Very VERY rarely do hosting providers provide the platforms, tools, or database(s) necessary for this kind of hosting. You can't just use a "web host".
@ALiveVam said in Need help about Install:
Is the installation process different from PHPBB?
Yes, different in every way. Really nothing similar between them from techniques to technology.
@ALiveVam said in Need help about Install:
i already finished reading nodebb documentation.
It's pretty easy to do once you read through that. From reading that, you can assume that all of the prerequesites needed like NodeJS, NVM, MongoDB, REDIS, and the NPM modules are not available from your web host. I know of no web hosting that provides for ad hoc platforms or NoSQL databases, that's just not a thing. Calling something a "web host" implies that they do not support this but only do MySQL/MariaDB and PHP.
@ALiveVam said in Need help about Install:
i want to install nodebb at this night.
Two fast options...
@scottalanmiller said in Need help about Install:
Use NodeBB hosting. This is how they make their money, but you have to be on their shared infrastructure. No random shared hosting company will provide what you need, it's way too complicated and specific.
Awesome reply....
All my confusion has been gone.And I got my answer.
@ALiveVam said in Need help about Install:
@scottalanmiller said in Need help about Install:
Use NodeBB hosting. This is how they make their money, but you have to be on their shared infrastructure. No random shared hosting company will provide what you need, it's way too complicated and specific.
Awesome reply....
All my confusion has been gone.And I got my answer.
Glad that I could help!
Yes, using their hosting is very easy and affordable and you get support right from the official source 
@scottalanmiller said in Need help about Install:
our largest site has hit 191 million hits in a month.
Holy. shit.
@Bri said in Need help about Install:
@scottalanmiller said in Need help about Install:
our largest site has hit 191 million hits in a month.
Holy. shit.
That's a record, normal months are only 20-25m.
@Bri We have what is rumored to be the single busiest thread in NodeBB history as well..
Just curious what the architecture is behind it? Is that pure NBB + 1 beefy VPS? Varnish? cluster?
@Bri said in Need help about Install:
Just curious what the architecture is behind it? Is that pure NBB + 1 beefy VPS? Varnish? cluster?
Not a cluster, just a single VM. Yes, quite beefy. MongoDB, on CentOS 7, on Linode. Nginx in front along with CloudFlare on a commercial account (more features.) We keep RAM high enough that we never swap, and we are on screaming fast SSDs in RAID 10.
We were prepared to go to a cluster, but found that we can't push NodeBB reasonably to a point where we need more horsepower!
@Bri said in Need help about Install:
Varnish? cluster?
No Varnish. We use Varnish in some non-NodeBB web hosting stuff that we do, but never looked at combining it with NodeBB.
Actually still on MongoDB 3.4 as well. Really need to get that updated. Just haven't had time. We plan to migrate to Fedora 30, MongoDB 4, and Vultr at some point. But that takes time, and we are busy
Hope your backups are good 
I'd recommend setting up static file serving on nginx, but I bet you do that already.
