How are Campaigns managed in Sales Cloud and what is Campaign Influence?

Campaigns track marketing initiatives and their impact on revenue. Key concepts:

1. Campaign Member Statuses are customisable per campaign (e.g., Sent, Opened, Responded, Converted) and one status is marked as "Responded".
2. Campaign Hierarchy allows parent/child grouping so totals from child campaigns roll up to the parent (up to 5 levels).
3. Campaign ROI is calculated as ((Actual Cost − Budgeted Cost) / Budgeted Cost) × 100 — the ROI % field is auto-calculated.
4. Campaign Influence links campaigns to opportunities to show marketing's contribution to revenue. Models include: Primary Campaign Source (only the campaign on the opportunity), First Touch / Last Touch / Even Distribution models (via Customisable Campaign Influence). Admins configure influence models and time-decay rules. The campaign on the Opportunity's Primary Campaign Source field and the Contact Roles' associated campaigns determine influence credit.