Cloning is when you take a inner tissue piece of an actual mushroom stem, and then use that isolated Heterokaryotic cluster as your mycelium source. You will experience much MUCH more substantial yields this way. Heterokaryotic simply means that two germinated spores come together or "mate" to become one organism that is able to produce spores. You can also do true isolations by grabbing up single germinated spores and mating one isolate to another on purpose. This is true "cross breading" although it doesn't always result in a perfect 50/50 split of traits, it simply means that they Heterokaryotic form is now sharing traits from two separate substrains.
To start spores into action to get mycelium, you can just order a spore syringe from a trusted place and then use it to innoculate some brown rice flower jars. Check out the instructions in my signature below for a very simple method. I HIGH recommend using
www.spores101.com or
www.mushbox.com for your mycology needs as they have always treated me very well. I hope this helps.
Also, if you have trouble finding good help about shrooms you can check out shroomtalk.com and just browse their posts. It is a great resource for new growers since people there are nicer to noob growers than most other big shroom forums. Good luck!