build language pack

I am looking for a reliable document that helps me to build a language pack on Ubuntu 18.04.

I got translations form (http://download.documentfoundation.org/libreoffice/src/6.2.0/).

How can I compile/build them and concert to mo files for LibreOffice 6.2.0?

This site is for question and answers about LibreOffice usage. Yours is about development, so you will probably get a quicker answer if you ask it in a developers’ forum/mail list.