Can you distribute trample damage among multiple blocking creatures before assigning excess to the player?

When a creature with trample is blocked by multiple creatures, the attacking player assigns combat damage. Under CR 509.2, you must assign at least lethal damage to each blocking creature before you may assign any damage to the defending player (or planeswalker). Lethal damage means damage equal to the creature's toughness minus any damage already marked on it (CR 702.19b).

You have full freedom to distribute the damage among the blockers in any order and any amount, as long as each blocker receives at least lethal damage before any excess goes to the player. This means you can choose to give one blocker exactly lethal damage, another blocker exactly lethal damage, and then send the remainder to the player — or stack more damage on one blocker if you prefer.

Importantly, you do not have to assign excess damage to the player — you are only allowed to once every blocker has been assigned lethal damage. If your trample creature's power does not exceed the total toughness of all blockers, no damage reaches the player at all.

Example: You attack with a 10/10 Trample creature. Your opponent blocks with a 3/3 and a 4/4. You must assign at least 3 to the 3/3 and at least 4 to the 4/4 (7 total for lethal). The remaining 3 damage can be assigned to the defending player. You could also assign 5 to the 3/3, 4 to the 4/4, and 1 to the player — any split works as long as each blocker gets at least its lethal amount first.

Relevant rules: CR 509.2 governs combat damage assignment, and CR 702.19b defines how trample interacts with the requirement to assign lethal damage to blockers before assigning to the player.