Developing WordPress site behind a static site

I’ve now solved this by:
1) copying my index.html to the /old/ directory (and updating navigation in other pages)
2) Installing a “Coming Soon” plugin, (this one) which, to my surprise, let me override the template and paste in the entire content of my index.html page.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)