Hello Albert.
No you should not run the 'user installation' section, that's more of an 'expert' option (maybe I should remove that from the Readme, those who have any use for it will know it's there anyway, and you are not the first to be confused by it)
If you have run all commands without any errors, then you should be all set. Maybe it's the 'localhost' address that needs explaining?
The 'localhost' part of the URL means 'on this computer', so you need to run the browser on the raspberry for that to work. To open pellmon from another computer you need to know the ip address of your raspberry, which could be something like eg. 192.168.1.8. Then you go to
http://192.168.1.8 on any computer in your local network.
To find out your raspberry's currently used IP address you can run the command 'ip addr show' in a terminal on the raspberry. The output will look like this:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether b8:27:eb:d2:0d:80 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.8/24 brd 192.168.1.255 scope global eth0
valid_lft forever preferred_lft forever
The IP is found in this row:
inet
192.168.1.8/24 brd 192.168.1.255 scope global eth0
Hopefully you now have PellMon open in your browser, but there is more... The raspberry is by default set up to use a 'dynamic IP address', that means it will ask your router for an IP address every time it is started, and will most probably get a different IP every time. This is not very useful, so to be able to use PellMon efficiently you will need to change the IP address to a static IP, which is then always the same. We can continue there when you have it working with the dynamic IP.