Now i do want some trading, but the commodities screen is not yet understand by me
I am in a system .. trading in system itself make no sense i assume ( caannot oversee this now)
Import and export is between systems, so i what has my system to offer for making credits on a "export" flight to another system and then back ?
You want to do it on easy mode or with ingame tools?
Easy mode: https://eddb.io/trade/single
Ingame: several options.
a) open the galmap, select trade routes and look closely who trades what with whom
b) you can get the prices and profits for trading between stations you have visited inside the commodities screen - rightmost column, on top, you can select one other market/station to compare prices to
c) for simple and profitable runs, find systems in outbreak and ship in basic medicines (usually available cheaply in boom-ing high tech systems) or find systems in famine and ship in foods (likewise, from boom-ing agricultural systems).
Finally (not really recommended for doing in a starter Sidey) you can check out rare goods. There are some goods that are only produced in limited quantities at one single station, like Lavian Brandy (Lave Station), Leestian Evil Juice (George Lucas in Leesti) or Hutton Mugs and Mega Gin (Hutton Orbital in Alpha Centauri). The further away you ship them, the higher the price is paid (up to ~170 ly distance).