What is the best way to implement responsive design?

Question

HTML

Hello!
Such a theme - we made a small redesign of the site, now we need an adaptive layout.
What is the best thing to do - make the layout separately at the layout designer, or immediately give the PSD layouts to the programmer, so that he makes up and implements everything on the site?
There is a typesetter, but there is no programmer who can also typeset! it is necessary to make up from scratch, since the old version was not adaptive

Answer 1

They wrote a symphony for violin and trombone.
What's the best way to do it? Hire a violinist and a trombonist, or give the trombonist both parts?

Answer 2

A layout designer who cannot make "adaptation" is not a layout designer.
Let the layout designer do everything according to the layouts. If deadlines are burning, then of course order on the side.
Pull the layout on the CMS and display all the content from the database - let the programmer do this already.