Fouls and cards? Criterion...

[nesta17]

Please, some one explane me:
- Yellow and Red Cards give for count fouls or what?
I mean... Let see the pictures/pic 03 and 04 are from the same match/, statistic match and sub stat about fouls and cards.
All matches are in same group in Chamions League:

[drazen vtc]

Just refferee judgement, dont think they have var

[nesta17]

Yeah, and this is so strange too for me! 21 fouls = 1 yello card. I remember my matches, when i have one foul, withiut injuries for the enemy player, but reffere color me with red card