Urgent: Collect e-mail now, start later with automation

Hi,

Please help me with the following.
I want to start collecting e-mail adresses right now with people who are interested in my challenge. I want to collect them now and start the challenge later (in 2/3 weeks). What do I need to do?
Put hem on a certain list and add that list later to the automation?
Please help me.

Greetings,

Nick