Our introductions were seven days. Day 1 spend an hour at foster care, day 2 a few hours, day 3 spend a morning and do the morning routine, day 4 spend the evening and do the bedtime, day 5 foster carers bring them to your house for a sleepover, day 6 a break so baby can have goodbyes with foster carers, day 7 collect them and take them home. That's usual for most people I know. Some do do bumps, where adopters turn up at the park or something a few times so baby recognises you.
Our foster carer put our pictures up around him too, at his level, in his cot etc so he was constantly seeing our faces. Prior to introductions we did video calls and although he didn't really interact with us on the calls, he heard our voices. We also sent voicenotes so our voices would be familiar to him. You create a scrapbook as well with photos of your home which foster carers can show them. It is really well thought out to be honest, it's not just swoop in and take them.