Tick anything you already have, in any order. Quests unlock once this is done.
Detecting without the owner's permission is theft nearly everywhere. A polite ask at one farm is worth more than any upgrade to the machine.
Find a detecting club near you3 things left above. Quests are real things you go and do, so they only make sense once you have what you need.
First one waiting: Grid-search a field and cover it properly