From within the Desktop client you can activate Staking for your wallet(s) by clicking on the Staking switch after your wallet is fully synced.
Please understand that depending on how many Zano you have, it may take many days before you will get a staking reward, until that time it seems to look like nothing is happening. When you get a staking reward it will look like this on your History tab:
There is also a Staking tab which looks like this:
And when you go to: https://explorer.zano.org you can find the Real Time APY, you can find it in the top right corner, it looks like this:
Here is also an excellent video about Zano Staking