Bicycle loading

For the last ten plus years I have cycled around town with lots of thing strapped to my rucksack and other stuff under my arm or hanging off of the handlebars [not always to the happiness of the police officer as I cycle past]. But recently I treated myself to a pannier to make life a little easier. I'm not sure I've quite got it worked out though as everything keeps falling off. This was today's effort. I was picking up some supplies for a trip but I didn't quite line up the foam blank [yes, that is a heel dent in the end where I kept kicking it.] I need a bit more practice at stacking I reckon [and a few more straps. One just isn't cutting it.]