You gain the basic spellcasting benefits (page 150). Each time
you gain a spell slot of a new level from this archetype, add a
spell of the appropriate spell level to your repertoire, either a
common spell of your chosen tradition or another spell of that
tradition you have learned or discovered.
So ... you gain 1 spellslot and 2 spells known per 'milestone' ?
I believe this should be in the Second Edition rules discussion forums, not Third-Party.
As for your question, where are you getting 2 spells from? For each spell level you have a slot for, you'll have one spell in your repertoire. The basic spellcasting benefits don't grant you any spells known by default, only your spell slots.
dang I misklicked
And I realised now where my mistake in reading the whole thing was
*facepalm*