If you are not starting with powdered ingredients then of course you must pulverize them using a mortar and pestle or coffee grinder. Electric coffee grinders produce too much heat, allowing for the loss of vital chemicals from our ingredients and therefore shouldn't be used. Also, most resins will break the blades of electric coffee grinders.
Woods are very difficult to pulverize with a mortar and pestle and really require the use of a hand crank coffee grinder of some sort or simply beginning with powdered woods.
If you are just starting out making incense mixtures then you should keep the number of ingredients down to three (3) to begin with, perhaps one wood and two herbs, or one resin, one wood and one herb, etc. As you get used to making incense you can slowly expand the number of ingredients you use.
So the first step is to choose the recipe you will use and gather the ingredients needed.
It’s recommended to pulverize your ingredients by "class" by grinding woods first, then herbs and saving the resins for last. Resins, if young and soft, will make a mess of your mortar and pestle and its best to keep freezing them to get them powdered. It’s also recommend saving them for grinding last, which allows you to grind everything in your recipe before you have to clean the mortar and pestle. Weigh each ingredient in the recipe after grinding, and then keep one bowl for all the dry ingredients and another for all the resins.
Mix all your dry ingredients together first (herbs & woods), separately mix all your resins together then add your resins mixture to your dry mixture and mix together thoroughly. I like to throw the completed mixture into my mortar and pestle again and grind it all together one last time to help blend the aroma of each ingredient into the others.
Congratulations! You now have a "loose non-combustible incense mixture" and are ready to enjoy the aromatic treasure you've just created. Its recommend aging mixtures for a couple of weeks, so that all the aromatics permeate into each other and produce a single bouquet of fragrances. You can heat this mixture as it is over charcoal.