Clicker training is something that I have just started doing recently and have found incredibly helpful, especially with off-lead work. The point of clicker training is to more accurately communicate to your llama the very moment that they have completed the behavior you are looking for. This is why it is especially helpful for off-lead work, you can click to tell your llama what they just did was good even when you are too far away to give them a treat.
To clicker train your llama start by having your clicker in one hand and treats in the other. Do a pattern of click, instantly give a treat, click, instantly give a treat, etc. Once they realize that the click means they will get a treat you can ask them to do a simple behaviour that they already know, such as kush. As soon as they do the behaviour, click, and then give them a treat. This teaches them that the click means they have done something good. You can then move on to use it as a reward in every aspect of your training. You will hear a click in all of my videos each time my llama does something good.