Congrats! It should tell you on your formula tin. I use SMA gold and it says 3 oz (or 3 scoops) per feed and baby should have 6 of these in a 24 hour period. Most babies feed every 3-4 hours but it could be more as your little one is only a few days old.
Although it's written for breastfeeding mums, the principle is still the same. Remember to hold her close, look into her eyes and enjoy the fact that you're nurturing your little one as you feed her. Try not to force her to take more than she wants - her tummy is really tiny - so little and often is better than trying to make her go a set number of hours.
Yes - feeding her according to her 'requests' is the way to go and you will become better at ascertaining what she wants as the days go by The pack info is a very general guide and it's not 'one size fits all' but it's a useful starting point.
Is your midwife still available to help you with the details on all this, and to help build your confidence in person? You could ask for a visit if you are unsure.
i had the same prob when my son was born...didnt have a clue! One i was giving my son 3oz every couple of hours but he seemed to want more, asked one midwife she told me to stick to 3oz, went the next day feeding every 2-2.5 hours... was knackerd. The next midwife said to up the amount to 5oz see if he took it, he did and went quite happily for 4hours. After this i had my son on regular feeds of 4.5oz every 3.5-4 hours, i swear the fact that he never cried for milk helped him sleep through earlier. i didnt like the idea of feed on demand, but thats personal choice! My advice, go with your gut!! Do what feels right for you and your baby!!!
The problem is that while it can be "easier" to encourage them to take more than they should be having (and some babies will just keep eating as it's harder for them to self-regulate with the fast, continuous flow of a bottle), it's not necessarily healthy for your baby. Little and often, following their cues helps you to bond, to tune in with her little cues and communications, and will mean that you're following more of the way that her tummy is designed to be fed if she was breastfed. It's designed that way for a reason
Tanking up with milk to try to get her to sleep longer does have its potential risks and downsides.
Of course, go with what works for you, as long as you're aware of all the pros and cons.
3 of my DC were FF from quite early on. (earliest 3 days and latest 3 weeks) I started with 2oz in the bottle and always increased it so they were leaving less than an oz in the bottle, but never 'encouraged' them to finish bottles, just let them take what they wanted. I also fed on demand, which for DS1 was every hour for quite a while.