Since you're having real difficulties with this one, I'll help you out a wee bit.
If the decision awarded was "offside", this would have resulted in an indirect free kick to Scotland.
The actual decision awarded was a direct free kick (see graphic below), for a foul - as displayed on screen and as fed to the commentary by UEFA officials.
Here ↓ the arm gesture which accompanies a direct free kick. Honest to god, the concept of this is basic, it's a real shame you can't seem to grasp it.
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And for further weekend reading to help enhance your knowledge of the rules of the game (no need to thank me):