You can no longer cast spells of 1st level or higher normally, instead, you can “set” these spells in one of three forms; Glyph, Ward, or Rune. The following are the rules for setting spells:
Glyph: A glyph is set on an object or surface. You must choose a surface that can support the application of magic in order to set a spell in this way.
Glyph Triggers: Pressure, Proximity or Timed.

Ward: A Ward is set on a creature or object. You must choose a willing creature or object that can support the application of magic in order to set magic in this way.
Ward Triggers: Attacked, Proximity or Timed.

Rune: A rune is set on a hostile creature or on a surface. It must be an applicable surface or the creature needs to fail its saving throw to be set in this way.
Rune Triggers: Timed, Action or Activation.

Glyphs, wards, and runes are visual representations of written magic wherever they're placed. They're always visible, unless visually blocked by heavy obscuration or cover. A set glyph or rune on a surface always takes up the space of a 5-foot square on that surface, while a set glyph, ward, or rune on an object or creature conforms to the size of that object or creature. A visible glyph, ward, or rune can be identified with an Intelligence (Arcana) check at DC 12 + the spell's level.

There can be no more than 3 glyphs, wards, or runes set on an object or creature in a single 5-foot square, regardless of the object or creature's individual sizes. There can only be 1 set glyph or rune on a 5-foot surface.

Set spells last until triggered, or until you prepare spells or otherwise finish a long rest, whichever happens first. Set spells that disappear due to you preparing spells or finishing a long rest do so harmlessly.

The following are the rules for triggers and their general application:
Pressure: This triggers if it is stepped on or attacked directly. The DM may also rule other extreme forces from a falling object or pushed creature can also trigger the set magic.
Proximity: This triggers based on any creature entering proximity. You determine the proximity in increments of feet, up to the spell's range. If the spell has a range of self, the proximity range can be up to 5 feet. You can choose to have the set spell ignore you when you initially set it, and during your turn at a later time to then count you for its proximity.
Timed: This triggers based on a set timer, determined by you. The timing must be set in increments of rounds, minutes, or hours. In combat, the increments are based off your turn in the initiative. You cannot set a spell to go off at a precise time, such as noon.
Attacked: This triggers based on whether or not an enemy takes a hostile action against the warded creature. This trigger has additional definitions that must be clarified: it can trigger from an attack roll or a saving throw, but not both. The selection is made when you set the spell.
Action: This triggers based on whether an enemy does or does not take a predetermined maneuver. The maneuvers that can be chosen in this manner are attack, cast spell, move, or item interaction.
Activation: This triggers based on whether another glyph, rune, or ward is triggered. The corresponding set spells must be within 30 feet of each other in order for this trigger to function.
When you set a spell, you or your familiar must be able to touch the surface, object or creature. Setting a spell takes the same casting time as normally casting it would. For spells that require a reaction to an event, you instead use your reaction during your turn to set it. A spell set in this manner uses the applied placement as its point of origin for the spell, and is triggered as long as you can see both the set spell and the trigger. You choose targets, direct area-of-effects, or other such interactions as normal once a set spell is triggered. If the spell has a range of touch, or requires an attack to be made, the range is determined from the set spell's placement, not you. For example, a glyph of Mage Armor, when triggered by proximity, can only be used to affect a creature that is within touch range of the glyph, provided you are able to see the target when it's triggered.

When a rune is set on an unwilling creature, they must make a saving throw if the spell would normally have one. If the spell would not normally have one for a creature, then they must make an Intelligence saving throw against your spell save DC. If the creature fails this save, the rune is placed on them and, should it be triggered, they suffer the spell's effects. They do not receive an additional saving throw when the spell is triggered.

When you set a spell that requires concentration, you do not concentrate on it until it is triggered.

Set spells are considered hard cast and interact with effects that require casting a spell when a set spell is triggered, not when they're set.