Hello Quiiil.... oh well...
1) Unfortunately characters can't be customized much since there aren't different clothes: you can wear armours of various kind, namely light, medium and heavy and magic robes. Probably you could start wearing a light armour.
2) Right click with mouse on the diamond icon you should see in the upper left corner of your screen until you see all the available icons. Then you can click on the icon named "shortcuts" (it's appearence could vary depending on the skin you choose). From there you can set a lot of shortcuts, spells included.
Let's say you want a shortcut for "flame burst": right click on an empty slot. Choose a name for you shortcut, for example "Flame Burst" (
) then insert the command:
/cast k-factor flame burst
where k-factor is a number between 0 and 100 and it's the power of the spell. 0 it's the default ( and the suggested value if you are not high skilled in the Magical Way of the spell, in this case Red Way ). k-factor is optional, thus you can simply type
/cast flame burst
Then choose a comfortable shortcut key.
When done, confirm the changes.
3) Currently Klyros can't fly
4) If you are under Windows, try right clicking the launcher icon and choose "run as administrator".
I hope this will help you and... welcome!