No connection to mqtt and node-red on raspi 2B

[pampasadmin]

Hi all,
I'm new with docker, so I followed the instructions on git-hub step by step. Starting with a Zip-copy of the repository I build up a directory on my raspi. Building the container seems to work, because a "docker ps" shows the status of ctnodered and eclipse-mosquitto as "up".
So I assume, that the images are working - however I fail to open a connection via web browser. I checked a couple of URLs and port without any success (localhost, 172.17.0.0, :1883, :9001).
so at the end the question is: how do I access mqtt and Node-Red ?
I have no external devices via Zigbee etc. connected, at the end I want to read out some values of my heating control over the network via wget.
Some version info:
Docker Version 19.03.6
docker-compose version 1.25.4
Although the project is not brand new I hope for feedback.
Cheers Uli

New status a couple of hours later:
I repeated the procedure from scratch again - but now I started the start.sh script with sudo. After that I checked the container with portainer and now a complete url for node-red is displayed - and it works. So the original problem is resolved, no idea why.
It seems to be essential to create the container as superuser. However it is quite hard to find out the reason of "not working".
Now I will start my trials with node-red.