If you're trying to train your entire team, it will be VERY slow and it isn't worth it IMO. For single position training, you should start with 2-3 18 year olds that play the same position. If you want guards, get young guards with star potential or higher for now (same principle goes if you want to train bigs). You don't need to break the bank at this point for young trainees.
For full training, your trainees need to have 48 minutes each week at the position of the skill you're training (PG if you're training Passing, for example).
For the positions you aren't training, buy them on the market. Be careful though, because it's easy for new players to get ripped off if they aren't wise with the kind of players they buy.
All I can think of for now. Good luck (sent from a mobile phone).