1. "Avada Kedavranexa"
I sincerely hope you know how to pronounce the first part of this spell. The second portion connects to the tail-end of the killing curse and is said as "neksə".
This curse is cast at the sacrificial victim. It begins the ritual but does not specify the creation of a Horcrux yet. It kills the victim and traps their energy for future use. After using this spell, the caster should feel a crackling aura of magic around them. It is important to quickly proceed to the next step before this aura dissipates.
Wizards or muggles may be killed to make a Horcrux; the magic itself does not discriminate between blood types. I suggest using a muggle, because they are easier to overpower, but a wizard makes for a more satisfying kill.
2. "Anima Sectumsempra"
(ah-nima sectəm-semprə)
Basically, this spell means 'divide the soul forever' in Latin. Readers may recognize 'sectumsempra' as a cutting curse that creates gashes in a victim's body, but that was never its intended purpose. It was first created as part of the Horcrux ritual. The cuts are an example of the dividing action being performed without a specifier, which in this case is "anima", meaning soul or animating principle.
As I have mentioned before, this spell creates pain and the sensation that one is being torn in two. This is normal. The caster should attempt to retain their intent and concentration.
3. "Egressus"
(eg-res-əs)
Literally, "come forth". While saying this spell, the caster must envision only the torn portion of their soul emerging, or they will perform the equivalent of the Dementor's Kiss on themselves. If the spell is done correctly, a glowing sphere similar to an extracted memory (but larger, and possibly tinged with red) will appear at the tip of the caster's wand.
4. "et skafos"
(et skahfohs)
'to the vessel', or something of that sort. I think it's from Greek this time. This is actually a continuation of the previous spell. As soon as the ball of light appears, the wand must be touched to the intended vessel. At this point, the caster's pain should diminish slightly.
5. "sigilum"
(sij-il-əm)
The final spell of the ritual. It finishes the process, seals the soul fragment into its vessel, and imbues the vessel with the qualities of a Horcrux.