The Goal: Locate a suitable planet for colonization, colonize it, enjoy life in the new colony, and so on.
The Plan: 1. Have a bitchin' flying saucer that also goes underwater.
2. Use it to visit hundreds of worlds apparently at random, until stumbling upon Earth. Observe, evaluate for habitability and resistance capabilities of native population, etc.
3. Periodically recharge magnetic power at the North Pole, because the saucer runs on magnet power.
Supplementary Tasks: Kidnap Earth people as specimens to take back to home planet. Their body structures will be studied for potentially useful adaptations to immediately copy via genetic engineering, like evolutionary CliffsNotes.
Contingency Plan: Blow up any and every submarine that tries to get near the North Pole. If anyone manages to invade the ship, melt them with rays. Failing rays, chop them in half with automatic doors. [NOTE FOR FUTURE EXPEDITIONS: Do not allow an Earth man with a flare gun anywhere near the saucer captain's massive, undefended gelatinous eyeball. Though it can regenerate, this hurts like a bastard.]
Is the Plan Sound?: Not too shabby, but not particularly colorful. A big speech about how specimens are being collected seems at direct odds with the primary observed behavior of destroying everything in the saucer's path.