I would say at the start there are a few urgent things to do.
1) Cut the deadwood. 90% of your starting team is rubbish. Try to cut them down to about the 5-6 best players sell or sack the rest, but make sure you are getting rid of the right guys - maybe ask someone experienced.
2) Decide on a training position, as a new player who says he has no idea the easiest thing to train is either PGs or Cs. Choose one. It looks like you have no-one worth training on your starting team. Then buy a level 4 trainer (spend less than $20,000 to buy him and try to have his weekly wage as close to $10,000 a week or less as possible). Then buy three trainees - that will be three young players you will want to train.
My minimum standards would be (and more is always better) maximum age 19, minumum salary $3,500, minimum potential allstar. For PGs height no more than 6'5" and for Cs height no less than 6'8". Skills, none listed less than 5 (mediocre), for PGs outside defence, jump shot, jump range and passing for Cs inside shot, inside defence and rebounding.
Obviously if you can get a 6'0" 18 year old PG with superstar potential and all skills at respectable, go for it! But I would not spend more than $100,000 on anyone. You only have $250,000 and a lot of demands.
Read up on how to train.
3) Check your arena prices before tuesday. You will want to adjust them.
4) Buy some solid but cheap players in your non-training positions to round the team out to about 10 guys. Try to spend $20,000 or less on each of these unless you can land a star - but watch out for guys with high weekly wages that you can't aford.
5) Look at your league and your position and make a plan for where you want to end up this season.
6) Post back here for any more help.
Good luck!