NEC-TM has only a basic Admin-Interface, but no translation interface. It is designed to serve as a TM-engine via API access for other servers and thus is a perfect match for translate5. Optionally the same TM on NEC-TM can be accessed through translate5 and other CAT-tools.
More information about NEC-TM you find at https://www.nec-tm.eu/
Installation under Ubuntu 18.04
Install docker
Install docker as outlined here:
https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-on-ubuntu-18-04
Install NEC-TM
Create NEC-TM directory
sudo mkdir -p /opt/nectm/elasticsearch_data sudo chmod -R aog+w /opt/nectm/elasticsearch_data
Install NEC-TM
sudo docker pull nectm/activatm:latest
This will run a while 
Run NEC-TM for the first time
sudo docker run --restart=always -p 27979:7979 -p 27878:7878 -p 19200:9200 -v/opt/nectm/elasticsearch_data:/elasticsearch_data --name nectm -t nectm/activatm:latest
The "restart" part of the command will ensure, that docker automatically restarts NEC-TM in case of system reboot or failures.
Automatic (re)start of NEC-TM at system boot
For instructions on how to do an automatic (re)start of a docker container like NEC-TM please use this manual:
https://docs.docker.com/config/containers/start-containers-automatically/
Configure translate5 for usage of NEC-TM as Translation Memory resource
Configure NEC-TM for usage by translate5
See the instructions here at the bottom of the page