Alright, the sentence would be "Okay, I like to sing." Make sure the first letter is a capital (so O instead of o). You need a space after the comma, so it's not "Okay,I" it's "Okay, I." And you need to include the word "to" when it's a verb that you like to do. Lastly, you also need to have a space after the full stop, so it isn't "sing.And" it's "Sing. And"
So that message should be
"Okay, I like to sing. And you?"
If there are any words I say that you don't understand, please ask.
I play piano and saxophone, and I sing a bit. Do you perform your singing, or is it just a hobby?