The Scenario Information Panel gives you information on how this scenario was designed. At the top the name of the scenario and author are given, and possibly their e-mail address. If there is version information on the scenario, this is given too.
There is then a blurb of color text describing the scenario in play terms. This should give the history setting, and some hints as to the objectives of each side.
Lastly the settings of a number of scenario play switches are described.
Allow Convert Neutral. If enabled, this game lets you conquer new territory. Worlds that start off as netural can be overcome and added to your pocket empire. If not enabled, then you are restricted to conquering the worlds that start alligned at the start of the game.
Allow Omniscent Sensors. If enabled, the entire game board can be seen by all players. This is handy for beginning games, or ones where the warring states are not related to the general civil information spreading network. If not enabled, you will only be able to see ship deployments in systems where you have ships yourself, or that are on your side.
Allow Fleet Reconfiguration. When a scenario is started you start off with the ships that were given to you by the scenario designer. If this parameter is enabled, you are free to scrap any or all of those ships and build ships of your choice, up to the same cost value. If not enabled, then you are stuck with the fleet you start off with.
Allow Intrinsic Defense. If enabled, then worlds have a defensive rating equal to their population digit. This reflects the civil defense of the world working against the aggressor. This makes worlds easier to defend and harder to conquer. Neutral worlds all gain this benefit. If not enabled, then it is assumed that the conflict is not one that the citizens of the worlds are passionate about. They will work for whoever last had ships in the system.
Allow Construction. Some games are about ship building, others are not. If enabled, you can build new ships at appropriate starports in your pocket empire. If not enabled, then you must do your best with the ships you start off with.