How do you green diamonds?

So many questions....
I suggest you read through the guide here to familiarize yourself with the game before proceeding further since you seem not to know what to do.

I'm not sure what you mean by 'green diamond' but I think you mean 'how do you get it above a sim' to do this you simply tap on the sim then tap on things you want it to do.
There are many ways to get money but a super easy was is to use the construction o coins to buy a fire pole and sell it.
To get Children you need to buy a crib from the children section in the home store.

For making money,
1. Connect to Facebook. (By clicking the three dots in townmap then click the lock-thingy then connect to your facebook accout.)

2. Buy NBR (neighbor) things in shop. As you can see, you can buy infinite Items in the shop using nbr. Nbr doesn't decrease as you buy!

3. Buy it many times. 50x if you can. (I prefer to buy the taekwondo-thingy. It costs 8nbr)

4. Go to townmap then click the three dots again. Then un-connect your Facebook accout.

5. Go to the place where you bought the things using NBR and sell it all!

(I prefer the taekwondo thingy because when you sell it, it costs 1000simoleons.)
Note: to get NBR you need Facebook friends that play Sims freeplay.

It was probably Quests.. You can get money by purchasing packs in the store.