Hi guys, i'm new to the site and i wanted to thank you so much for helping me to find the manga that i want. But I still dont know how to filter the tags yet. does you guys know how to do it? I can only use one tags per search and i saw there are some url that include more than one tags.
Can you guys show me how to do it? TIA

On the right you'll see Genres and Categories links. Click Genres. On the new page you've got a bunch of genres. Just above the Action you'll see "Advanced Search by Genre". Click it. You'll get a lot of search criteria like genre, license option, type etc... What you want to use is the Categories/Tags box and genre.
For genre you just check mark the genres you want to exclude or include (green for include, red for exclude). For the box you put one tag per line.

E.g:
Female Protagonist
4-koma
Absent Parent/s
-Young Female Lead

The - in front of a line will exclude any manga with that tag
If you know what tag you want to use but don't know what this site calls it (maybe it has a / in it somewhere) you'll use the Categories link on the right.

Hopefully that is somewhat helpful.