First of all, decide which wallet you want to use, dashcore or an app.
Then be sure to protect your wallet with a password/pin and that you have your seed written down when talking about the app.
Then go to one of the exchanges to buy Dash and withdraw them on an receiving address on your wallet.
All is accessible via the wallet, receive, spend etc...
Read more on docs.dash.org as this is our wiki page.
Jeremiah Okoro