Jordon - looking at your previous posts it seems you are already racing 5k distances.
For intervals there are a few different ones you can do depending on the purpose of the session, the distance you want to race and where you are in your training. Given your age I would keep the reps you do reasonably short, definitely not above 800m and plenty of rest.
A simple one is 400m reps. For example 8 x 400m with 90 seconds recovery between each one. Looking at your 5k time of 22:20 the recovery will be roughly similar to the length of the rep.
The aim is to be able to run consistant times throughout the session slightly faster than you would be racing at so dont kill yourself on the first 2 trying to max out as the last ones will be slow as well as painful making the session less constructive.
