Your Campaigns page (creators.thecirqle.com/creators/collaborations) lists open campaigns you can apply to under "Eligible to apply". A campaign shows there when it's open for applications and you match who the brand is looking for, such as your country. If you don't see that tab, there's no open campaign for your profile right now.
New campaigns open regularly, so check back often.
Brands can also invite you directly. Invites arrive by email and show under "Invited to join".
Check that the country and gender in your "Profile" settings are right.
Connect your accounts under "Social Accounts" now, so you're ready to apply when the right campaign opens.