Who is the seller Professional Beauty?

If it doesn't say in the Amazon add then I don't know but really who cares. It works beautifully.

Do you use water in it?

No. No water. It is basically a curling iron that rolls the hair into curls. I use it all the time.

How to use the nano titanium

There are videos and content on the existing detail page that should help you understand how to use the tool. Of course each unit ships with an instruction booklet as well. Below is a snippet from the MiraCurl2 instruction book: INSTRUCTIONS FOR USE • Ensure hair is dry and combed through. • Plug the styler into a 120V outlet. • Slide the temperature switch to the required heat setting. • The styler is ready for use when the ON indicator light has stopped flashing. • Turn the steam function on if desired. Refer to "Steam function" and "Filling the water reservoir" sections. • There are 3 time settings; choose the optimum setting for your hair type. Alternatively, switch the time setting to 0. • Select the curl direction by sliding the control to either position L, R or A. • Separate a section of hair that is no wider than 1 inch (Figure A). Ensure that the section is clean, dry and combed through. • Please note the styler must be positioned into the hair with the opening of the curl chamber facing toward the head (Figure B). • Position the styler where you want the curl to start. The hair section must be straight, and placed neatly through the center of the styler (Figures C and D). • Once the hair is in place, let go of the hair section and close the handle to allow the hair to be automatically taken into the curl chamber (Figure E).