I don't have a masternode, so i can't explain how to set up a masternode, but there's plenty of good topics on that.
To start mining without masternode, you just have to download the wallet, set it up and save it (so you got a record of your DP wallet in case you have to DL it again).
Then you unlock the wallet with your 12 words password, and it starts stacking on his own !
for the record, i just took 2500 DP, and i earn 8.33 DP every 1 or 2 days now that it's working.
I'm guessing masternode (25.000 DP) is way more valuable, but i don't have money to put in it right now
maybe one day !
Edit : You also have to send your DP on your wallet, didnt mention that part...