Add every load you want to power. Running watts is normal operation; start watts (surge) matters for motors, AC and pumps. Check switchable for loads you run one at a time / stagger at startup.
Sizing model: running load sums all simultaneous loads plus the largest switchable load. Surge capacity adds only the single largest start-watts (sequenced startup, never all surges at once). Recommended output covers running with margin and must cover surge.