The best way to make sure the loader installs easily starts with taking the loader off. Make sure it's on firm level ground. If the loader is not stored on firm level ground re-installation can be a bear.
When you are putting the loader back on, if you have already used the bucket curl function, use the boom cylinders to line up one pin at a time. Once you make the first pin, you should be able to use the boom cylinders again to line up the second.
If one pin is higher than the other, you need to use the bucket and the boom functions to get it to line up. Just make the low pin first, then the higher one.
Starting on level ground saves a bunch of aggrivation.