Brand new Mutisite setup change from subdomain to folder structure ...

Hello,

I just set up my first Multisite ever and it worked very well. Unfortunately I used the subdomain setting to create it ... but I wanted to create the new blogs in a new folder.

I found in the wp-config.php the setting "define( 'SUBDOMAIN_INSTALL', true );".
Is it enough to change this value to true to get the blogs installed in folders instead of subdomains.

I just created one blog as a test and it did not work (of course not as I don't have the subdomains ... haha) ... so I just deleted again the blog and swapped the value to "false".

I created a blog but it came out in a funny format (like no css loaded -which also could be related something else).

What do you think ... should I reinstall Mutisite or is it enough to swap the setting to FALSE?
What could be the problem with the formatting?