First off, if you just started using KSE, make sure you save a backup of your savegame. It is far too easy to ruin your game using this program if you don't be careful.
Let's see here, the most common and least dangerous ones.
Locate the savegame you want to change and expand that one. You can safely change the Player Name, Appearance, Portrait, Soundset by clicking on it. To your right, you'll either see a text box where you can enter your selection or choose from a list of ingame options. After you choose the one you like, hit Apply. If KSE pops up an error message, make sure you do not hit Apply, or you will ruin your game.
You can change your attributes by expanding the Attributes box. Select the attribute you wish to change, edit the text box on the right, and hit Apply. Just make sure you don't get carried away with increasing them too much, as there is an upper limit to them. I think it is around 250, but it'll make the game too easy. The same goes for the Skills box.
You can also edit the force powers, feats, and inventory your character has. For powers, expand the Classes box, then the Force Powers box. You'll see a list of powers to your right that you can add to your character. Select the power and hit Add New Power. You can also remove powers in the same way by using the Remove Power button. Note, in order to use the advanced powers, such as Force Storm, you first have to select all the prerequisite items, else it will not work properly.
For feats, expand the feats box, where you'll get yet another list of feats. Follow the same procedure to add them in, though be aware that some feats are character specific, such as Assassination Protocols being unique to HK-47. While you can use them, it is a bit unrealistic. Hit Add New Feat to add, Remove Feat to remove. Note, as with force powers, in order to use the advanced feats, such as Master Flurry, you first have to select all the prerequisite items, else it will not work properly.
I'm pretty sure by now you'll know what to do with the inventory box. Be aware though that the inventory box contains many items that should never be added the player's inventory. Be extra careful when selecting items there, and if you're not sure what the item is, it is safer to ignore it rather than add it to your inventory and ruin your game. Items in black mean they are in the game by default and are not in your inventory. Items in blue mean that they are in your inventory already. Items in red mean that they are either extra items added from your Override folder not present in the original game, or items that exist in your original game but have been overwritten by a file from your Override folder.
Lastly, you can edit the Experience, Good/Evil, Credits, Chemicals, and Components that your character has by selecting the appropriate box, entering the values you would like in the text box to your right, and hitting Apply.
When you're all done, simply hit Commit Changes, reload your game, and check if the changes you made took effect.
Categories that should not be edited unless you know exactly what you're doing would include the Area Name, Last Module, Gender, Globals, and Quests. Those areas offer the greatest chance of trashing your game.
Check back with me if you have more questions or need clarification. I am quite bad at writing tutorials on how to do stuff.
- Star Admiral