I have a matrix question where I want the table to look like as in the following picture. I know that I need to edit boxes and change the code. But I don't know how...

I would recommend using an "Array" question type and make something like the attached image or you can use the "Array (10 point choice)" for a number rating. If you want something closer to your image you presented I would either learn or higher someone who knows Javascript and make a script in the question itself to alter how it is presented.

See array with "Semantic Differential" - manual.limesurvey.org/Question_type_-_Array#General_description

tpartner wrote: See array with "Semantic Differential" - manual.limesurvey.org/Question_type_-_Array#General_description

tpartner hat's much better.
Sramos99 sorry for pointing at JavaScript