Please Help! How to turn golden blonde hair (orangy) to platinum?

It sounds like you used a box dye with peroxide, perhaps plus bleach to lighten, and the ash colour didn't take.  As you probably would know, going to platinum is very damaging to the hair and would need to be done in stages, so it depends on the condition of your hair now on what you consider doing next.  But I wouldn't use box dyes because the levels of bleach and peroxide are unknown, as are the results.

I'd say give it at least a week or two before lightening any further, but if you think your hair can take it, do a bleach bath for your next treatment and see how light you get, and coat with coconut oil a good couple of hours before bleaching to help protect the hair.  In the meantime, tone the oranges down with non-peroxide silvering products; there are lots to choose from, such as Provoke Touch of Silver and, though I haven't had loads of experience with it, I've heard some good things about Clairol Shimmer Lights.

If you post some photos, we may be able to offer some additional advice.  Good luck!

Also don't process your hair for at least a month to give it a chance to recover and for all the damage to show up.

Did you do this over previously dyed hair?

Blonde permanent dyes will only lift 3 shades max, so are only going to come out the expected shade on hair that is already blonde. It has only been able to lift your hair to the level 7/8 you are seeing, which is still too dark for the light ash tones to show. You need to lighten further to get past the orange stage. If you have old dye on the hair removing it first will make lightening much easier.