Ummm you need a guild so you actually have spies then you hit the cleverly named 'spy' button and choose an action Scout tells you their build and your chance of success Steal.......duh takes money Assassinate kills units making direct attacks easier to win
1. ninja suit. 2. Build guild 3. spy attack 4. fail to spy and tear down guild 5. pretend you had a forge all along.
You get spy attack and spy defense by building and upgrading guilds. You can also get spy defense from lookout towers.
Buy a guild. Upgrade it when possible. Then on the main menu click battle. When it shows a list of players click spy. Then choose the attack you want.
No offense, but if you don't know How to spy, then you probably will be better off with forges until you can spend like 200mil on guilds. This is a rough esemate of what they cost, I may be wrong.