How to organize vpn through vpn?

Question

Network administration

In general, the essence is as follows.
There is
1 User with Internet access (nat blocks incoming connections)
2 Server with Internet access (no restrictions)
3 User 2 with Internet access (no restrictions)
What is required:
Get the ip of the first user to the second user
What they wanted to do
1 user connects via vpn to server
2 the user connects to the server via vpn .
further 2 user connects via vpn to 1 user via vpn because nat will no longer block.
but something doesn't work. does not connect and everything.
Are there any simpler options to set something for user 1 and have all user 2 traffic go through user 1 . all these users have different providers.
Heard about reverse tunneling but never understood.
if there is a similar question or links to Google, I will only be happy

Answer 1

I found a simpler option
avz.org.ua/wp/2010/06/29/putty-how-to-make-your-wi...

Answer 2

weedy grass. vpn is always higher priority. we reflect further.... lifts on the user 1 vpn the server and we forward port on the gateway. and spitting everything plows!