Best way to use flows for pre-launch?

Hello Klaviyo Community!

I am planning to start a new product and I’d like to get some pre-launch traffic and do a giveaway.

Here’s what I had planned:

Social Media Traffic > My Site > Sign up form > 7 step email flow with a few giveaway reminders, pre launch email and launch email.

But what I hadn’t considered (its my first time using Klaviyo) is that I won’t be able to set particular days for some of the emails. So that makes planning impossible since everybody will join the list at a different time and I can’t set the dates for the giveaway, its end or the launch itsself.

So now I am not sure how to set that up?

Any suggestions would be highly appreciated!