Unless you plan on harvesting, don’t worry about vested vs. unvested.
If you transfer 100,000 XEM (the currency of NEM) into your wallet, you would have a balance of 100,000 XEM unvested, and 0 XEM vested. After 24 hours, 10% of your XEM would become vested, so you would have 90,000 unvested, and 10,000 vested. You must have a minimum of 10,000 XEM vested in your wallet before you can harvest, so you would be able to harvest at this point. After another 24 hours you would have 81,000 unvested, and 19,000 vested, because you would take 10% of 90,000 (9,000) and add it to the vested balance (10,000) and you get 19,000. This process would continue until you send or receive funds. If you send funds, a proportional amount will be sent from your vested and unvested balances, so if you have 81,000 unvested, and 19,000 vested, and you send 10,000 XEM to another account, then you would see 8,100 sent from your unvested balance, and 1,900 sent from your vested balance.
If you receive funds, 100% are added to your unvested balance. After 24 hours, 10% of the new funds, and all other funds in your unvested balance will become vested, and then again every 24 hours thereafter.