today i've a match and i've some other questions.
The -1 command for 20 cm enemy unit also count character models?
Enemy UNITS in 20cm. It is not like a character is scary enough to cause you troops to react

unless you'd play Warhammer

If some stand are defended and some no how to roll?
I know there is several different ways this is handeled, so at the least discuss with opponent. In general our methode of playing is that the attacking unit still gets "charge in open" bonus IF it contacts a stand in the open, the round fought is like normal, assuming all attacking troops would hit the most vulnerable stand if they could.
Stands that are partly in terrain; optionaly no charge bonus, no defence bonus OR allow charge bonus, but to hit determined for defended troops.
If one of my unit can charge enemy on the flank , but just reach i must place one stand in contact on the flank and the other rear the first?
that would count on the front as well. after placing your first stand into contqact, remaining stands must move to their FULL capability to contact on battleline. If they can not, then they need to move to remain "in formation" with the rest of their unit
If i pursuit i can place other stand on the battle line?
to complicated to handle here, do a search on pursuit for some posts that already handle this subject