There are a total of 10 Ramen Delivery levels which can be gotten from the ramen shop. The first couple of levels are pretty easy and only consist of 3 deliveries. At the later levels you have to complete 5 deliveries and some of them require some trial and error. Also make sure you have Level 3 Chakra Concentration to be able to climb high buildings. One of the levels also requires the ability to walk on water. You'll learn this ability later in the game during the main story.
Now, the real pain will be Level 10. You need to deliver Ramen at 7 different locations. I used the video shown below and only needed to try twice (I screwed up first time). Credits to gemkaifan for creating this video.