Need help on the installation process.

I am circling on the base configuration page.

When I enter my datas and press 'update config file', I get the 'We cannot automatically update... ' message.

Ok. I modified manually my _config.php file, and upload it on my hosting.

The process tells me (step 7) to 'call the installer from scratch'.

Ok. Ther comes the page with my updated data. And the button 'Update config file'.

And again the 'We cannot automatically ...' message.

How can I launch the installer without this attempt of file updating ? Did I missed on button ?