
You can look them up, but you can also discover them by figuring out the grammar and meaning of the spell runes and extrapolating from there.
There are several spells you can cast the game never directly tells you about. Pre-casting combat spells and manually casting utility ones is a good way to go about things. Your lines can be any length (shorter is faster and more reliable), you just have to pause a fraction of a second, and then start your next stroke at a clear angle to your last. Spellcasting is not purely about making the glyph as the game shows it to you, it only really cares about the corners. Make sure to get them repaired on time if you're using bows actively. There are no separate arrows, quivers simply go down in durability as you use a bow. A Shovel is needed for one or two sidequests as well, but you don't need to lug one around all the time. In addition to excavating valuables from walls, one can be used to break down various environmental objects and obstacles. It's worth holding on to the first Pickaxe you find.
Make sure to buy the Key Ring from the general store in Arx, it'll function as every key you use on it and saves you a lot of inventory shuffling. Hold Shift to move item stacks, and press the "Use" key (F by default) on your inventory icon to open all your bags at once once you've found extras. It's not until you get there that you'll get reliable access to potionmaking, a wider range of spells, heavy armor, competent weapons of every type, and a broad range of consumables. Everything will be a bit shaky at first until you make your way to the big human settlement and get a chance to stock up on supplies. Arx Libertatis makes the game play nice on modern systems and fixes some bugs. Had to go up close to detonate fireballs, otherwise they will keep building and chew up my entire mana pool, leaving me nothing with which to sustain invisibility long enough to escape. Also key is using the environment - since it is dark, and it is easy to get Hidden status in Arx Fatalis, I hid the character to regenerate mana and repeat the hit and run. The key here is not to exchange fire because they can cast Paralyze at any time, and sometimes chain it between the two of them so you are stuck for a long time. Try it.) Tactic here is cheese - hit and run, with emphasis on RUN, augmented by Invisbility so they can't track me and stop pursuing. (You may wonder how he equipped Achanta's Long Sword with his stats - cast Bless first to get stats to meet the requirements. Got to King Poxsellis' Tomb early for his helm (even before finishing the Troll Strike).