Hi there,
As far as I understand from your post, you may have misunderstood some things about risk management. And that's totally fine, considering that when you start doing this there's a thousand new bits of information coming at you every day.
Long story short, the theory is not that you shouldn't SPEND more than 2% per trade, but rather that you shouldn't RISK more than 2% per trade. Let's take an actual example: You have 25K so 2% of that is $500 risk. Say you want to long a stock at a price of $10 and you put your stop loss at 9.50$. This means that you risk $0.50 per share, and given that your max loss per trade is $500 (2% of your account), then the calculation you have to make to decide how many shares you can buy is 500/0.50=1000 shares.
Now, one thing I'd add is that, in my humble opinion, risking 2% of your account per trade is way too much, particularly when you're just starting out. Think about it, merely 10 losing trades and your account is already 20% down. I would consider the option of only risking a fraction of 1% because risking too much per trade can throw your psychology off balance in the middle of a trade and make you focus more on potential losses that you aren't comfortable with rather than the proper trade management that you need to produce consistent results.
Hope this helps 🙂
Vlad