Hi. The first thing you should do is trim your roster down to about 12 guys. Put the other guys on the transfer list or fire them. Having 23 players is unnecessary.
As far as getting your guys into the right positions, their suggested position is a decent guide.
PG- passing, outside defense, handling, and jump range are what I consider most important.
SG- jump shot, outside defense, jump range, and handling
SF- jumps hot, driving, outside defense, rebounding
PF- inside d, rebounding, inside shot, and jump shot
C- inside d, rebounding, inside shot
so look at your roster and see which players you have with those skills as their highest. Until you figure things out, base offense and man to man is a good way to go, tactically. That said, you have one guy, your center, who is a monster for d.V. You might try playing inside isolation.
Once I scored a basket that still makes me laugh.