Normally you make very simple assumptions here and assume these are percentages of revenue, operating expenses, or cost of goods sold. Examples:
• Accounts Receivable: % of revenue.
• Deferred Revenue: % of revenue.
• Accounts Payable: % of COGS.
• Accrued Expenses: % of operating expenses or SG&A.
Then you either carry the same percentages across in future years or assume slight changes depending on the company.