The sages of Svarog have always known the runes, and always written down what happened with the followers of Svarog. It has been this way at least since Gradoslavl, however it is said that even older chronicles exist in the monastery of Sviatogor.
The populace of Triman is taught reading and writing by the sages, so most peasants in this setting are literate.
There are two types of runes: the old runes, known mostly to clergy and scholars, that are used in magical rituals and old church scrolls, and the peoples runes, that are used for everyday writing. Most magic scrolls will be in old runes, however one can use the peoples rules for magic spells as well. If you do so, there is a greater chance of the ritual producing undesirable side effects.
The peoples runes will be ordinary latin alphabet. Everyone is considered to be literate, and can read and write in peoples runes. The peoples runes resemble the old runes in many ways, and are a simplified reworking of the runes in-game. If your character is to know the old runes, you will be provided with the alphabet by the organisers in advance.
If you don't know the old runes, you can still try to replicate them, guess their meaning or try to translate them into peoples runes