There are 7 scenarios in the William Wallace campaign:
1. Marching and Fighting
2. Feeding the Army
3. Training the Troops
4. Research and Technology
5. The Battle of Stirling
6. Forge an Alliance
7. The Battle of Falkirk
Win every scenario of the campaign using the cheat code “i r winner”. Then, to trigger the achievement, win any scenario of any campaign without using cheat codes. The quickest scenario is the 1st scenario of the campaign: Marching and Fighting.