As mentioned above, P/E multiples are a shortcut for DCF.
If you have a steady business (no growth, but no decline) it should be worth roughly 10x owner earnings.
Throw in some growth and you might justify a P/E multiple of 15.
Some extreme high growth companies like Google & Facebook in their heyday justified very high P/E multiples.
I believe that every beginner should verify what I said above with DCF models and get a feel for the process. Once you get a feel then you will not need DCF.