So, this is the biggest mistake that I notice when I see videos of people struggling to make spring rolls. They take the rice paper and dip it in water over and over again thinking that they need the sheet to be completely soft before they add the fillings. But then it just ends up being floppy and you can't add anything.
So, all you really need to do is to get the whole sheet wet once with warm water. Then add in your favorite fillings and by the time you're done, the rice paper is ready to roll. If it's still not as soft as you'd like it, just wait a minute or two and it should be good to go. I hope this helps and if you have any other questions, just let me know!