Select the BO you want to train
Click "Train" in the lower left of the "Status" Screen of the officer
Now click on whatever skill you want to train and it'll give you a drop down for what officers you can train that skill to.
Select one and move on to the next.
I am a science Commander
my science officers are LT commanders
I have t9 points spent into 'scientist' that the tooltip tells me allows me to train science team III
however i am unable to train any of my officers, the train button is grayed out.
I get the overlay message "You do not have any skills to train to bridge officers"
To train two things are required. First is you having Rank 9 in the appropriate Captain skills. Second is having a BO of the proper profession AND the proper rank. Most of the Player train skills are Lt Commander level skills for BO. So you BO have to be a Lt Commander before you can train them on the skill.