Solid in bottle

Fatimah • Cooking baby #3 and #4⏳
So I went to my doctors today 
And she told me to start giving DD
Solid.my baby will turn 4month on the 15th
But she has severe acid reflex
And doctor think it will help.
Because we tried everything.
Anyways my problem is 
She didn't tell me how much in each ounce?
She just said 2tbs in 6ounce 
Anyone else giving their child solid yet?
Rice cerial