Have a look here. I have also some trouble to get the stack working, but maybe you find something usable.
About certificates I got a nice explanation from htdvisser at slack:
For Let’s Encrypt certificates, The Things Stack needs an acme directory where it can store the ACME account and certificate data. All you have to do is
$ mkdir ./acme
$ chown 886:886 ./acme
In docker-compose.yml that ./acme folder on your host is mapped to /var/lib/acme in the container.
And in the configuration of The Things Stack, you´ll tell it to use that /var/lib/acme folder
The first time you connect to The Things Stack using TLS (HTTPS), it will request certificates from Let’s Encrypt and store them in that folder
So, I you use LetsEncrypt and have a domain, all you need is the ./acme folder. All other lines referring to local certificates should be disabled.