When you log-in and you go to select your new skills, do the following.
1) read what each skill does
2) read it again
3) go to a skill planner and map it out (I posted a link to a really good one in the forums)
4) go to the stobuilds subbreddit and read the numerous threads on the subject or wait for Davis to get on vent and bombard him with questions :)
5) be absolutely sure that the skill you are selecting is the one you want. If you select one wrong skill, you're stuck with it unless you want to spend a respectable token. You CANNOT use the shopping cart method as before.
6) re-read 1-5
If you follow 1-6 and you still screw the pooch go to step 7
7) go to STO, right-click, and click un-install (that was for you Mr. Hau)