Venofer infusion questions

I have suffered with very low iron for years and years now and just had lab work done showing a ferritin of 4 (iron and saturation % also quite low). I’ve had 2 infusions done in the past and I can’t remember the type/brand, but I do remember they each took 3 hours. This was many years ago. Next week I go for a Venofer infusion. The woman I spoke to on the phone said that I would be in and out within 15 minutes. I know this kind of infusion is much quicker, but don’t they need to keep you for a bit to make sure there’s no reaction? She didn’t tell me how to prepare either, can I eat beforehand? Anything I should do afterwards? Also, I thought these were supposed to be done multiple times in a relatively short timespan? I only have this single infusion scheduled.