Using AppleTV Remote On New 4k Appletv

1-How can I prevent the apple tv remote power button to stop turning my TV on and off?

Not using the power button would prevent that. There are other methods to set to sleep. You may also need to disable CEC to not power up or down connected devices together.

Sleep or wake Apple TV - Apple Support

2-Old AppleTV interface whne I did a search for movie or actor name there was an option to clear the whole string. Does not seem to be there on new device and have to delete character by character the string. Is there a way to clear it completely like old interface?

In any of the Search fields:

• Press-and-hold the Select button with the Backspace ‘key’ highlighted, will fast delete the whole search query.
• Use Siri to replace the previous query each time.

3-I can't find option to go to movies and genre like old interface. Is there a way to find that.

Not sure what you were used to.

• The Search app can search all kinds of searchable things, including apps, but also movies and genres.
• In-app Search in the TV app or Movies app can search for titles, genres, cast, crew, within that app. The Search tab in the TV app will show tiles for popular genres and categories (like presets).

4-Trying to learn new interface and remote the instruction fold out is very limited. Any more place to get all details?

See: Apple TV user guide - Apple Support

1-So not sure what disable CEC is can you explain. Now I turn on TV then press apple power button which is ok. Seems after turn TV off apple tv goes right to sleep is that correct operation?

Consumer Electronics Control (CEC) - Wikipedia

Each HDMI device that has support for CEC functionality, should very likely have an On|Off setting for that.

- For Apple TV: Settings﹥Remotes and Devices﹥Control TVs and Receivers﹥On|Off

- For other devices (TV, audio system): See their manuals.

If supported on each device, then they may send and receive commands to other devices. If certain CEC features are not supported on a device, then that command will be ignored. If CEC is set to Off, then that device will ignore all received commands, and not send commands to other devices.

If you do not want all HDMI devices to go on|off together, then you may need to turn off CEC on some or all devices. CEC is a bit all-or-nothing, without further fine-tuning by the user. Not all CEC features may be available on every device: each manufacturer makes feature decisions for each model device. All CEC features are optional, nothing is mandatory, although ‘power-on’ and ‘power-off’ (sleep/standby) are pretty common.

2-Search delete string. don't know the remote yet which is the "select" button and which is the "backspace" key?

The Select button is the center of the Clickpad, when pressed deeper than just touch, to a real click. Use your Siri Remote or Apple TV Remote with Apple TV - Apple Support.

The Backspace key referred to the on-screen keyboard, with the ‘character’ next to ‘z’:

Also old interface had "wish list" to add to and genius recommendation in menu choices. is that gone?

There is a Wish List in the Movies app (but not in the TV app) on the Apple TV box.

There is a separate Wish List in the iTunes Store app on iPhone and iPad.

There is a Recommended List in the Movies app on the Apple TV box. I find it remarkably accurate, although I have seen much of it already outside of the Apple apps (e.g. cinema visits, blu-ray discs).

The Watch Now tab in the TV app is a mix of promoted content and recommended content based on your watch history (e.g. popular genres for you).