Are there any rules on the creation of a shield guardian?

Question

Are there any rules related to the creation of a shield guardian?

I am aware of the creation method for the amulet. But I'm asking about creating the actual construct.

Answer 1

No, the shield guardian has no specific creation instructions

Unfortunately, as of yet, the published 5e resources contain no instructions or indication as to what is required to actually construct a shield guardian. There are a couple of different downtime rulesets you can use for crafting magical items (as seen in the DMG and in Xanathar's Guide to Everything), but these both depend on knowing the item's rarity (which is not given for a shield guardian), and anyway a shield guardian isn't an item, it is a creature.

As Bloodcinder suggests in this answer to a related question, a DM who wants to enable their player to create a shield guardian could refer to an existing magical item, the manual of golems, which enables construction of thematically very similar creatures:

For example, it would be reasonable for a DM to look at the rules for the manual of golems magic item in the Dungeon Master's Guide (p. 180-181) for inspiration. The rules list the time and cost to make a particular kind of golem in the Monster Manual, and these expenses increase with the challenge rating (CR) of the golem. The DM could create a manual of Shield Guardians with comparable expenses based on the Shield Guardian's CR 7 in relation to the golems, plus the effort and expense of creating the amulet to control it.

Besides the spell simulacrum (which can only create a construct that is a duplicate of an existing beast or humanoid), the manual of golems is the only method given for creating magical constructs. Using this as reference, one would figure that creating a shield guardian should cost between 50,000-65,000gp and take somewhere between 30 and 60 days of effort (falling as it does between the CR 5 flesh golem and the CR 9 clay golem) as well as requiring the use of a specific manual.