I think it's a well written piece rookeis will enjoy and follow without any problems, but there are some parts I disagree with.
Get basic staff for doctor and PR.
PR manager rarely makes enough money to justify his salary, so I think he's not necessary. You would rather buy one more player and win the games before your home games to boost your attendance.
Investing in players. A balanced roster around $70,000 total salaries makes sense in low div 5 to win a title. You want 3-4 starters in the 10,000 range. Consider players ages 32+. They will cost less to buy which is important early.
You contradict yourself here because buying 32+ players is not investing. Unless you call money from advancing a return on your investment, which I tihnk it's not.
If you buy old players, you basically have to replace them once you advance. This means you sell them for much less money than you bought them for, effectively losing money in the process. Then you have to buy a whole new roster.
Solution would be 2-position training for first 2-3 seasons until the rookie manager becomes comfortable with training. This will not only provide him with more good players down the stretch, but also not make his trainees expensive salary-wise as a lot of rookie managers mismanage one-position training.
Look at your standings in your league. See if you have the chance to win the title this season. If no invest in the arena. If yes invest in starters.
Even if I had the chance at advancing, I wouldn't. Because this means I would have to buy old players who are good for your current league, but useless unless backups in higher leauge. But the main reason for waiting a bit more is 1) making your trainees ready for higher league and more importantly, 2) when you advance, you get something I call "golden season". I.e. roughly until all-star break your fans reward your title with massive arena attendance even if you are losing. if you don't give yourself time to build an arena first, you won't be able to sell all the seats you could and this will make you lose money.
Imagine if a rookie manager advances in his first season. Suddenly his old players are not good enough for new league and their skills are dropping. He can't train effectively as he's losing games because of it. He cannot build arena fast enough to capitalize on advancement AND he is facing demotion which punishes you with much less attendance.