I'd recommend the following steps:
1) Find the skill "Learn Portion" in category "Spells - Spell List Acquisition".
2) Click on the edit button that appear to the left of the skill name when you hover over it.
3) Click on the specialization button that appears during edition mode (it's a curved arrow, it should be the second button that appears to the right of the skill name).
4) Enter the name of the Spell list you want to learn.
5) Develop ranks in that new skill.
6) After level up is complete, make the spell learning roll (this step is not included in the current version, you have to roll and check manually).
7a) If the spell list was not learned, you just leave the ranks there for the next level.
7b) If the spell list was learned: first use the edit button to manually remove all ranks from the "Learn Portion (your spell)", then you might need to add the learned spell to the corresponding category (click on the edit button of the category, click on the plus sign to add the new spell list). Once the spell is in the skill list, use the edit button to manually assign as many ranks as levels learned (10 for Pick A, 5 for Pick 5, etc.)
Of course, for those using individual spell development, you just need to assign ranks to the corresponding spell skill during level up.
I hope that was clear enough, let me know if the steps answer your question, and thanks for asking!
