Wordpress Post order by date modified

[Abdomen]

Hello everyone,

I have a premium wordpress.com account and i'm trying to solve a important issue, essential for my website idea.

I need to have my posts in the front page ordered by date modified. I have read that by falsifying the date, it can be achieved, but unfortunately, i can't apply it, as i need to use date accuracy in my posts.

I tried the sticky note method, but all the posts with sticky notes activated, were positioned by alphabetical order!!

So i wonder, what can i write in the CSS editor to obtain what i need?
Is there some code allowing to change the order of those sticky notes?

Thanks for the time and patience,

Regards,

Ricardo