Help please

Good evening all, so my little one is 5 weeks tomorrow and he’s exclusively breastfed. I want to try and express a boy every day for dad to give at night... I’ve tried to express and literally get 1oz. I eat really well, porridge in the morning with fruit, healthy dinner and tea, snacks of fruit/veg in between and odd bits of sugar... donut etc. I drink at least 3/4 litres of water/sugar free juice a day. I’ve got a manual and an electric pump (medela)

Can anyone help???

How can I build my supply?

LO feeds 1.5/2 hours through out the day... he goes down at 9.30 at night, feeds again at 00.30, 4.30 and then up at 7.30 with a feed.