What Chess U.I Is This??!?

I'm not 100% sure, but in a few minutes of tweaking, I was able to get something VERY close with Arena. (I don't think the grain pattern in the wood matches perfectly, but it's close. Also, I noticed your photo shows white coordinate letters, but his video shows black coordinate letters. But you can change the color and font to almost anything.)

Here's my Arena tweaked version:

Oops, looks like I should have also turned off the shadowing of the pieces. A minor quibble...

What graphical elements did you use? Such as pieces and how did you get it like that

I think these changes should get you there (I used Arena 3.5.1):

In the menu, "Options --> Colour Scheme --> Wood"

Right-click on chessboard, uncheck the following:
Show Toolbar
Show Clocks and Logos
Show Movelist/Clocks/Statistics Area
Show analysis area

In the menu, "Options --> Appearance --> Main Window --> Other tab --> Uncheck "Use bitmap as background"

In the menu, "Options --> Appearance --> Main Window --> Colours --> Background --> Select the basic color of black, then click OK
(Note that if you use a black background, you'll probably have to change various text font colors from black to white. Maybe go with a lighter background color so that you can still read the black text fonts.)

In the menu, "Options --> Appearance --> Chessboard --> Marks tab --> In the "Last move" area, ensure that "Highlight last move" is checked, then check "Arrow", change the arrow width to 1, and finally, click on "Arrow colour" and pick a grey color.

The piece fonts should be OK the way they are, or you can use the built-in pieces instead of the TrueType fonts. I think the default pieces are TrueType fonts with the "Chess Merida Arena" design, size 77%. You can reduce the size a bit if they seem too big for the squares.

Also, in the menu, "Options --> Appearance --> Chessboard --> Squares tab, in "Additional" area, uncheck "Show Grid Lines".

Also also ;) , if you want to hide the menu bar, press the "Ctrl+Shift+F9" keys simultaneously. (To unhide the menu bar, press the keys a second time.)

If you want to change the coordinates font to bold,

In the menu, "Options --> Appearance --> Chessboard --> Additional tab -->" In the "Coordinates" area, click on the "Coordinates Font" button, and in the "Font Style" box, click on "Bold".

Here's a couple of screenshots with the move list reactivated.

The first one is a blue background and a black font color for the moves:

The second one is a black background and a white font color for the moves:

Can you pls say how to change font color too

Wow, I never thought this thread would get bumped after all this time, lol.

I now use Arena for Linux - I suspect the menu system is more or less the same as Arena for Windows. In the menu, "Options --> Appearance --> Movelist". You can change the colors for three different font settings: Moves, Value, and Comments.