Is that from the don't cry tab? The chorus? If it is, then don't care about the hammer on, just play it like an F. Sounds pretty much the same..
Or play the low 1 on the E string with your thumb, the 3's on the A and D strings with pinky and ring fingers, hammer on the 0 to 2 with your middle finger, and keep your index on the 1 on the b string.