II it possible to setup Ecobee in UDI if I don't have any Apple devices. I have setup Homekit node but I am still confused.

I need one of those for Dummies manuals really bad!

I will defer your core question to @Jimbo.Automates, but I think the answer is yes. If you installed the new HomeKit Plugin in EISY PG3, it will act has the HomeKit Hub without any Apple devices.

I highly suggest you throughly read all the Configuration instructions that come with these plugins. With both Plugins, go to either the eisy-ui Production Store or the eisy-ui Non-Production Store, find the plugin of interest and click on the button for that plugin and within that buy/trial/install panel you will see a 'More Info" button and you can read about the plugins before installing. If you already installed the plugin, then once installed (Trial or Purchase) go to the eisy-ui Dashboard, click on the plugin of interest and then click on "Configuration" tab and again Jimbo.Automates has really good instructions on all the setup process/options... all worth reading (in my case I read it many times).

HOMEKIT... The eisy-ui PG3 Plugin Production Store has the $30 purchase version for HomeKit. However, if you want to evaluate first, the Trial Version (one month trial) of the same HomeKit is still available in the PG3 Plugin Non-Production Store... always good to try before you buy. In my experiments with this plugin I did not have to modify any of the configuration settings and the HomeKit hub showed up in the EISY Admin Console and you will be able to see that it is connected if all is OK... still, READ the configuration instructions.

ECOBEE... Install the HomeKit Plugin first, then install the Ecobee plugin Version 4.1.3. Again, If you need to test how things work first, the trial version is still available in the eisy-ui PG3 Plugin Non-Production Store. the Production Store has the $30 purchase for the same version. The trial versions are great to test everything out.

Once the Version 4.1.3 Ecobee version is installed (Trial or Purchase) READ the default Configuration Settings in the configuration panel of the Ecobee Plugin in the PG3 Dashboard. During the configuration of the Ecobee Plugin... if the Ecobee is still PAIRED with any Apple Hub, you will have to unpair the thermostat before proceeding... see the Prerequisites Section In the Configuration Tab. I believe everything is covered well in the guidance instructions that are found in the Configuration panel for that Plugin in the Dashboard. the default settings should allow the Ecobee Plugin to function as intended, just check the Ecobee configuration quick-start instructions.

1 hour ago, 4481hoods said:

II it possible to setup Ecobee in UDI if I don't have any Apple devices. I have setup Homekit node but I am still confused.

I need one of those for Dummies manuals really bad!

@ISY4Me is correct, there is no need to have any apple devies. HomeKit plugin acts as a homekit hub so you can connect the Ecobee to it.