Healthy Start Card

[staryynight]

Just looking for a bit of help.
I applied for the healthy start card and it arrived the last week but I'm a bit confused by how I can use it.
If I'm doing my usual shop, which includes things that aren't eligible with the voucher scheme, do I need to pay for these separately or can I just put it all through at once and split the payment between cards?
I can't find a clear answer anywhere, I think because the scheme is new there is limited answers.
Thanks!

With the vouchers I would just give them them to take off first, then pay the rest on my bank card. They've never counted up to see exactly how much I've got thats eligible, but they can always see I have piles of fruit and veg. Different shops might do it differently though