I'm guessing you are talking about the Load screen tips...Like this:
Those are a feature just recently added to the game. Depending on what map is loading up, it may flash by too quickly for one to read. I find the TA, AvA, and SEA maps usually take enough time to load to allow me to read the tips.
I suspect they may make them easier to read in future game releases, but for now the only way to have them display longer is to select an arena that takes longer to load up.
That is different from the arena message. If you enter the training area, the arena message shows in a side tab of the clipboard. That one states the arena rules and other info. Most of the time in the main arena's there is no arena message, except when HTC needs to pass along information about a change in arena settings.
