How to make a felxible budget?

Robson Motors Performance Report for July, 2020 Budget Actual Variance Units produced and sold 20,000 18,000 $ 1,060,000 $ 946,800 (113,200) U Sales Variable costs: Direct material Direct labor Indirect labor Idle time Cleanup time Miscellaneous supplies 180,000 360,000 66,000 20,000 12,000 7,800 163,500 342,000 58,800 18,800 11,200 8,800 16,500 F 18,000 F 7,200 F 1,200 F 800 F (1,000) U Variable manufacturing costs 645,800 603,100 42,700 F Variable shipping costs Total variable costs Contribution margin 34,000 679,800 380,200 32,100 635,200 311,600 1,900 F 44,600 F (68,600) U (5,700) U Fixed manufacturing costs Supervision Rent Depreciation Insurance on plant 66,500 24,000 68,000 17,500 72,200 24,000 68,000 18,500 (1,000) U Fixed manufacturing costs 176,000 182,700 (6,700) U Marketing and other administrative costs 137,000 137,000 Operating income/loss) 67,200 $ (8,100) (75,300) U