If a current donation form use a drop down allowing donors to select with which Salesforce Campaign they wish to associate their donation and you wish to alter this so a single Campaign is selected by you in the administrator, you can do the following:
- Open the Soapbox Donation form you wish to customize
- Click the Integrations tab
- For Donor Chosen Campaign, choose No
- For Campaign, click Select
- In the popup, select one Campaign from the list with which to associate payments from this Donations form
- Click Select
- Once the popup has closed, click Save