Feeding solid food for baby !

Hi mummy, my reflux baby was 29 weeks now, we just started to feeding her some creamy rice and porridge. But she can’t have much and I didn’t feed her much at all . I only feed her 1 time per day, morning or afternoon, still she was vomiting on and off , I feeding her 1 hours 30 min or 2 hours after her milk . How you guys feeding your baby ? I really don’t know when go wrong! So upset see she have a vomiting after milk .