The path to Lichdom has three parts; a container called a phylactery(Soul-in-a-Box), a Lich Conversion Potion(G-ma's Lich Juice), and 1 certified-metric-fuck-ton of necrotic power(#LifeHack).   For the purposes of this explanation henceforth, the would-be lich shall be referred to as Steve.
Step 1. Place the Soul-in-a-Box within 5-feet of Steve.
Step 2. Arrange the dragon bones in a circle around Steve
Step 3. Cast #LifeHack upon Steve while he eats the heart.
Step 4. Steve then drinks G-ma's Lich Juice and dies.   If successful and Steve cast #LifeHack, Steve becomes a true lich, gaining the Lichdom Feat.   If successful and someone else casts the spell, Steve becomes a Lesser Lich, gaining the Lesser Lichdom Feat.   Ascended Spell. This spell costs 2 Spell slots to cast. An 8th-level spell slot and a 7th-level spell slot.