In Game settings:
Set Galaxy difficulty to beginner, game pace/research to normal and proximity to far.
Largest "map" your puter will play, game will tell you, set sectors to Galactic, Sector size I use medium Star freq. abundant.
For planets I set the first two at abundant and extreme planets to none.
Set Hostiles to none, set minors to none, for first game or two, minors will be the first option you will "change"/ add back.
Anomalies, relics, resources, and asteroids I set to abundant Nebulas to common, black holes uncommon and Accession Crystals none.
In advanced settings I'd check all.
In Victory Options unclick all but Conquest for now.
Next will be the opponents window choose your opponents do not under any circumstances choose The Drengin, Mimot, Festron, Corporate Sector, Xeloxi or Yor these are not races you want to have as opponents while you are learning. Also do not choose the Torian or Manti as they live on water worlds.
This is the basic advice I give to all that are new to GalCiv as well as any other 4X game.