How do I make a few simple changes in unit stats?

[Edi]

Read the modding manual. The basic commands you need are

#selectmonster [monster number]
[commands]
#end

Patches do not affect mods. A mod is an overlay on the core game engine. Meaning, first Dominions 3 loads. Then it checks if mods are enabled. When a game is created with the mod enabled, Dom3 then changes the core game stats to the ones indicated by the mod, i.e. it replaces them in that game, but the actual Dom3 executable is not changed. Only mod changes or mod conflicts will affect mods.