You can search by Google for this question.
What does staking exactly mean?
You need to have matured coins in the wallet (one more time, find out yourself what are matured coins), and add staking=1 to your .config file, then let your wallet fully synced with network and get active staking icon.
To get coins into the wallet.
It's not. The more actively staking time your wallet has in the network, the more chances to get more rounds of staking rewards.
The wallet has to be connected 24 h?
Good luck.