I need to analyze 3 months forecast budget, what informations should I provide first to begin my analysis?

Problem: I need to prepare a master budget for 3 months on merchandise purchases budget.What information do I need to lay out to start my planning?

1. Company 1- purchased a product for $30.00, resold it for $55 per unit. Expected
Inventory level of 2500 units on Dec. 31, 2005, is more than management's
Desired level for 2006, which is 20% of the next month's expected sales (in
Units). Expected sales are: Jan. 3500 units; Feb. 4500 units; Mar. 5500 units;
And April 5000 units.

I need to prepare a master budget for each of the first three months of 2006 for Monthly sales budgets showing the unit sales and dollar sales?