As regards over in Italy, there are a number of competing signs but if you follow the red/white ones you'll be OK. On this bridge there are 5 variants. The blue/white is for cyclists. The red/white for walkers. The European one is also for walkers are is considered "official" but there are far more of the red/white ones about. The other two (on the left) are far more sporadic so best to be ignored.
If you have a smartphone, a lot of walkers recommend the Sloways app which they have found useful. I use a different app but found that the signs far more comforting that an app.