It does not matter which side first but I recommend the top tape first. Plus I personally think it looks cuter with a low cut waist diaper. Congratulations you are done! On the back fold the back waist band down on the outside of the diaper. What brand of diaper is this? This makes a good seal around the legs and will prevent leaks from fast wettings that flood the diaper and take a few seconds to absorb it all. After doing that continue to hold the front in place with one hand so it stays snug between the legs until taping the top tape of one side.
See, that’s what the app is perfect for.
Some diapers have less plastic around the legs than these.
Putting the bottom tape of one side on, which can be tricky with some diapers. This prevents it from being scrunched on the side of your hip making it uncomfortable. I work as a mechanic and run my own company on the side.