Sure. I wont do like others and tell you its simple and read the manual.
Id rather show you that its simple.
Insert this into the BattleSim .map file:
(stuff after - is just comments and can be left out)
#specstart 31 4 - start Ulm in mountains
#specstart 37 10 - start Abysia in nearby mountains
#land 8 - wipe out the nearby swamp
#setland 4 - say where the next lines are for
#owner 31
#commander 114 - additional Commander of Ulm
#units 20 67 - 20 infantry of Ulm to him
#units 20 79 - 20 Pikeneers to him
#units 20 67 - 20 infantry of Ulm to him
#units 20 79 - 20 Pikeneers to him
#commander 113- Lord Guardian
#additem "Pendant of Luck"
#units 20 66 - 10 Guardians assigned to him
#setland 10 - say where the next lines are for
#owner 37
#commander 119 - additional Warlord
#units 20 81 - 20 infantry of type 81 to him
#units 20 82 - 20 infantry of type 82 to him
#units 20 81 - 20 infantry of type 81 to him
#units 20 82 - 20 infantry of type 82 to him
#commander 214 - Beast Trainer
#additem "Pendant of Luck"
#units 10 213 - 10 Salamanders assigned to him
Now start a game with that map, join as Ulm and Abysia.
Set the formations and scripts. Then have both armies meet in the nearby swamp
(I cleared out the local defense so you can see just those two battle).
Now start a new game with the same map, change formations, do it again.
Or edit the .map for new items or new troops, start a game and do it again.