Incredibly easy, just play against a level 10 legendary duelist, use balance skill, 5 monsters, and the rest trap cards that are NOT continuous or equip spell cards that fill up the field.
It’s not a stupid question but clearly it’s a question you’ve answered incorrectly. The requirement to unlock odion is quote Use A trap card 10 Time(s) in ONE Duel.
do missions against lvl 10 legendary character. build a deck that works - here find 10+ traps to put in deck that nearly do nothing, just letting you draw, give some LP or so. put 4 monster in deck so you wont get killed - monster 1400+ atk and you goood