Once a course exists, its Billing tab shows a plan summary card (with an Edit button), the plan's terms (Amount / Billing Cycle / Grace Period for session-based plans, or a Session Credits summary for packages), an expandable Linked Courses section, Invoices and Transactions tabs, running Collected / Remaining / Overdue totals, and two actions: Send reminder and Add invoice.

The Linked Courses section is the same mechanism used on the Group side (5.4): reusing one billing plan across more than one course pools them onto a single invoice with shared session credits, so this is where you'd see and manage that pooling for a 1:1 course too.