Read here some articles of howto do this and that in installing, setting up, administering and programming stuff in embedded and Linux computing. It is intended only to facilitate tasks which are more frequent.

Xenomai on a Beaglebone Black

In case of the need of a hard real time operating system in addition to a Linux OS, here it is described howto do that. Additionally the EtherCat library SOEM is also parrt of the system.

Realtime
Realtime Linux kernel on a Raspberry Pi3

Unfortunately the Raspberry Pi OS does not support a precompiled PREEMPT_RT patched kernel for armhf in their repositories. It is described here roughly how to do the task.

Realtime