How to build a like box on a Facebook page?

[33Q]

According to Facebook's Help Center, (see the link below)

Pages allow real organizations, businesses, celebrities and brands to communicate broadly with people who like them. Pages may only be created and managed by official representatives.

Groups provide a closed space for small groups of people to communicate about shared interests. Groups can be created by anyone.

You could start with a Facebook Group, which will allow you to discuss about starting your business, then create a Facebook Page when your actual company starts.
All the best to you. Hope this helps. God bless.