Hi All,
This might sounds stupid but I found a tones of tutorials how to use “Modes manager” but no tutorials how to actually “Set-up” Modes.
As explained “ hub is coming with 4 pre-set modes “Day, Away, Evening and Night mode” but no explanations (or I did not find it) of what actually means this modes (other that “names”. Can somebody tell me how to actually set up the mode itself and what devices is controlling
Example:
Day means that “specific” devices will behave in a certain way (the rest of them will behave as default, same applied for other modes for example a new mode “TEST” for example.
Thank you.
Modes are an Optional feature.
Modes generally are using Time as it's mechanism. The built-in Modes do nothing. In fact, left alone, they don't even change. Mode is nothing more than a word. You can compare that word in various ways.. RuleMachine, Motion Lighting, etc. basically in Apps.
You need to 1) decide you need, and want to use modes, then 2) cause the WORD to be changed based on.. whatever you decide. It's so wide open as to what you can do, it's difficult to create a one-answer. Yes, built in modes seem to be about splitting days, but you can delete all those words and use "Spring Summer Autumn and Winter" to split the year.
The Built-in App "Mode Manager" is intended to help you split days. You can create any number of mode WORDS and then use an app to shift between the words.
If, for example, you have a bunch of different Rule or Automations that do something at 7:30am, then you could have a Mode that changes at 7:30am and use Mode instead of Time.
Modes don't do anything on their own, only what you tell them to. Many apps have options built in to restrict their actions based on mode (e.g., "only run in mode X") or do something different depending on mode (e.g., "set dimmer level based on mode," which will give you the option of specifying something different for each mode). A common use for modes is to restrict lighting automations, and I'd guess that's why the default mode names are what they are. I don't use "Away" mode myself, but if you do, it's important to note that this is different from (but can be somewhat tied to--if you do so) Hubitat Safety Monitor's armed state.
You can add and remove modes (Settings > Location and Modes). I added "Evening" mode to the defaults but, besides not using "Away" mode (which I kept because I can't quite make myself get rid of it...), my use is mostly based on time of day, using Mode Manager (plus a rule for an odd case) to automatically change between them.
The above explanation is better than the rest of what I had in mind to say, so I'll just leave this here and hopefully both explanations are helpful!
( @bertabcd1234 I saw you starting to answer and truncated my explanation. 
)
Just to make sure since it hasn’t been mentioned you manage your hub modes via:
Settings / Locations and Modes / Modes tab
Yes, agree.. that's where the specific list of Words are added, deleted, altered. 
Thank you all so much for suck quick and comprehensive replies.
I was using Fibaro and Vera where modes have a different approach; I was confused when seen the modes that are actually just “words” in Hubitat and/or "conditions" to be used in “scenes, rules, devices, etc.”. Thank you all one more time
