The process of actually using an infuser is not a very hard one and even the novices out there should be able to pick up on it very quickly. In general, for every six ounces of water used you should use one teaspoon of full-leaf loose tea. So, whatever amount of water you plan to use, pour the appropriate amount of loose tea into the infuser. From there, take the infuser and place it in your teapot.
Now, go ahead and boil some water over the stove. Allow the water to sit for a bit before pouring it inside your pot. Once it is cooled for a bit (but is still hot), pour the water over the tea leaves in the infuser. That is it; now you simply wait the appropriate time and pour the tea when ready.