Paper requires Java 8 or newer to run. It should run fine on newer versions as well, such as Java 10, but certain plugins may have issues.
Migrating from Vanilla is easy, but there are some differences, namely in world saves. Paper (and CraftBukkit and Spigot) seperate out each dimension of a world (nether, the end, etc) into separate world folders.
Paper will handle this conversion for you automatically.
Paper is a drop in replacement for both CraftBukkit and Spigot, you don’t need to make any changes.
Paper provides runnable server jars directly from our continuous integration server here.
Download one of the artifacts (either paperclip.jar or paperclip-####.jar, they are the same) and save it to a new directory somewhere on your file system.
To run the server, simply start it up like any other Java application.
Open your terminal, navigate to the saved location, and then run
java -jar paperclip.jar
For more advanced Java tuning, see this page
To configure your server, see the Configuration page.