Extradimensional Spaces
The most sensible way someone might try to lock away such an effect is by isolating it in a pocket dimension such as one provided by a bag of holding or Heward's handy haversack. In these locations, the natural world would not be in contact with the book, therefore keeping its effect at bay until the party is ready to destroy the item.
Crafting Magic Items
If the party wants to craft one of these items, or build a similar one, there are two sets of rules. One is in the ...
Dungeon Master's Guide
which would require the characters be a minimum level between 3 and 6 (3 for the bag of holding and 6 for the haversack),:
a formula that describes the construction of the item.
... between 500 and 5000 gp (bag of holding would cost 500 and the haversack would cost 5000 gp), and the time to craft it.
This crafting is a downtime activity:
A character engaged in the crafting of a magic item makes progress in 25 gp increments, spending that amount for each day of work until the total cost is paid. The character is assumed to work for 8 hours each of those days.
Xanathar's Guide to Everything
Xanathar's Guide to Everything provides an alternate ruleset for downtime activities including new rules for crafting magic items.
To start with, crafting magic items with this ruleset requires proficiency with a relevant tool or with Arcana. In addition, you still need the formula like with the other rules, but you also need a special ingredient:
An item invariably requires an exotic material to complete it. This material can range from the skin of a yeti to a vial of water taken from a whirlpool on the Elemental Plane of Water. Finding that material should take place as part of an adventure.
The Magic Item Ingredients table suggests the challenge rating of a creature that the characters need to face to acquire the materials for an item. Note that facing a creature does not necessarily mean that the characters must collect items from its corpse. Rather, the creature might guard a location or a resource that the characters need access to.
Uncommon items (such as a bag of holding) suggest a challenge rating of 4-8, and rare items (such as a Heward's handy haversack) suggest a challenge rating of 9-12. Then, after this special ingredient, there is the standard gold and time cost which equates to 2 workweeks and 200 gp for uncommon items and 10 workweeks and 2000 gp for rare items.
Similar Magic Items
While a bag of holding or Heward's handy haversack are two RAW magic items that are the most fitting, there are rules for modifying magic items to make a more suitable container. In the "Dungeon Master's Toolbox" chapter of the Dungeon Master's Guide, the Creating a Magic Item section has a bit about Modifying an Item:
The easiest way to invent a new item is to tweak an existing one. If a paladin uses a flail as her main weapon, you could change a holy avenger so that it’s a flail instead of a sword. You can turn a ring of the ram into a wand, or a cloak of protection into a circlet of protection, all without altering the item’s properties.
You could similarly modify one of the existing extradimensional items to look more like the box your party is working on. In this way, the space within the box would exist in an extradimensional space, just like the bag of holding, or similar magic items.
How I would do it
Personally, my groups have found the Xanathar's Guide to Everything rules more rewarding as the special ingredient is very customizable and can make for a fun adventure all on its own. I think applying the rare rarity to the item (treating it like a Heward's handy haversack, would make a more interesting mini-adventure since you are treating the book as a major plot device.
Tracking down a formula
This is the first step, and the item that could probably be acquired by tracking down the archmage who may be able to advise the party on what method to use for the containment procedure.
I would probably have the archmage request aid from the party in exchange for his help on the containment (probably in the form of a quest) unless the party already has suitable renown.
Special Ingredient
This aspect is the most fun, and you could go all sorts of directions. I'd probably create an entire quest-line around getting this ingredient, likely involving a creature with a lair that the party would have to locate and conquer (either for an item in the lair or part of the creature).
My personal choice would be an Aboleth, because I think underwater adventures are super interesting, but you can find a full list of the appropriate CR monsters with lairs in this D&D Beyond search. Most of them are young dragons, so you could certainly develop some fairly standard dungeons where the ingredient is present in the young dragon's hoard.
Complications
One of my favorite parts of the Xanathar's Guide to Everything downtime rules are the chances of complications. Depending on where the party is crafting their item, you may want to introduce these complications to spice up the downtime of crafting (which could up to a couple of months depending on how many people in the party are able to work on it). The rules say:
there’s a 10 percent chance for every five workweeks spent on crafting an item that a complication occurs. The Crafting Complications table provides examples of what might happen.
But I may just force one complication to take place if the party isn't discrete about their crafting, as it can make the world feel more alive during these long periods of downtime, and creates some more interesting challenges.
