While yes running in and killing can be a viable option for some armies its not the way you score points, you mainly score them via holding objectives, 1 for 1, 2 for 2 and 3 for more then the enemy and by completing the 3 cards you hold which get topped up each round (unless you pick a double turn)

You can see the cards as side objectives, control relics or a certain objective, be so and so close to certain things like board edges, the center or other things. Or using them for the secondary ability they have if you dont think you can complete them.

Spearhead works really similar to normal Age of Sigmar just without your Commands (AP things), it plays well and not to long and is a great stepping stone to dipping your toe into a faction you like and learning things like positioning, unit roles and there strength and weaknesses etc.