An affiliate is a WordPress user with an affiliate record attached. There are three ways to create one, and you will probably use all three eventually.
They apply
Publish the registration form — the [squad_affiliate_register] shortcode, or the Divi 5 Registration module — and applications arrive in Squad Affiliate → Affiliates as pending. Approve or reject each one. You can set the programme to approve automatically if you would rather not gate it, which suits a programme where anyone with an audience is welcome and does not suit one where being an affiliate implies endorsement.
You add them
From Affiliates → Add New, pick an existing user or create one. This is for the people you recruited yourself, who should not have to fill in a form to join something you invited them to.
They buy first
Customer advocacy (Pro) turns a buyer into an affiliate at checkout. It is the cheapest recruitment there is — they have already paid you once, which is more qualification than any application form provides.
What they get
Every approved affiliate gets a referral link, a portal showing their clicks, referrals, earnings and payout history, and — if you enabled it — a coupon code of their own. The link works immediately; there is no propagation delay, because attribution is resolved on your own site at request time.
Rejecting well
A rejection sends no email unless you enable one. If your programme gets applications from people who genuinely misunderstood it, a short rejection notice saves you the follow-up question — the template is under Settings → Emails.