My shop is open, what should I do now?

Short answer: Two things: announce the shop to your community, and place permanent links to it in your website menu and in the header of your social media. Those links are not optional, they are part of what you give back for the shop being free.

Steps

Open the shop at its address, on a phone, and browse it the way a member of your organisation would. This is the last check before you talk about it.
Announce it to your community. Send an emailing to your contacts: see How do I send an email to my contacts. A post on your social media and a word at a meeting reach the people who do not read their email. Give the shop's full address every time.
Place the permanent link in the main menu of your website. That link has to stay there, not just for the length of an announcement.
Place the link in the Intro section of your Facebook and Instagram pages. An announcement post drops down the feed after a few days and can no longer be found: that is why a permanent reference is needed as well, somewhere that does not move.
Check the links the other way round: on the shop, the links to your website and social media appear right at the top. See How do I show my website and social links.

When to bring it up again

A single announcement goes unnoticed by part of your community. Plan to come back to it at the moments when it is already gathered: start of the season, registrations, the day before an event, kit handout.

The shop stays available at all times, and nothing about it expires. You can point people to it as often as you need.

Going further

You'll know it worked when: The shop is announced to your community, and a permanent link to it appears in your website menu and in the header of your social media.