I'm not sure what you did to the example server configuration that will cause the clients to get the same IP as the server, but that's certainly wrong.
Here's the relevant block from the sample configuration:
# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 10.8.0.0 255.255.255.0
Did you make the netmask at the end of the server
line 255.255.255.255 or something like that?
If you want to specify particular IPs to your clients, you can set up CCD files, where the name of each file is the CommonName on the certificates you've generated for the client.
In the server configuration, add in:
client-config-dir /etc/openvpn/ccd
If your client's certificate is named Client1, then you will have a file /etc/openvpn/ccd/Client
that has:
ifconfig-push 10.8.0.101 10.8.0.102
which will cause Client1 to get the VPN IP 10.8.0.101.