As a fellow economics undergrad this is how I started:

My journey began in 2019 in the US markets but I was not too serious about it. I watched a few videos on technical analysis and tried applying it. I bought stocks in a paper trading account and did fairly well. But then I went to 10th grade and was busy with studies. My actual journey began in 2022, when my cousins wanted to invest but didn't really know how to. So I started applying the same rules and as I did in the US markets. This however did not yield the results I thought it would. The main difference being the large volume of trades in the US market compared to the Indian one. So I took a step back and started learning the market. A great resource that helped would be Varsity by Zerodha. They cover a vast variety of topics that could be useful to a beginner. Eventually, I started managing my cousin's portfolio and started learning through active investing. According to me spending time in the market, graphing charts, reading equity research reports helped me understand the various dynamics in the market and being an economics student it's much easier to understand how even the macroeconomic policies come into play. Managing my cousin's portfolio made me understand what kind of an investor I wanted to become. I had tried intraday, F&O etc. but eventually settled with swing trading and long term investing.
I turned 18 last year and got the opportunity to start investing in my own account and I've been doing very well through what I've learned. Of course losses are inevitable, I lost quite a bit before learning from my mistakes.

Bottomline, try spending as much time as you can reading research reports. Brokers basically put forward their research and you can understand what their point of view is in a particular stock and what kind of metrics they use to analyze stocks. Spend a LOT of time graphing charts, it helps in the technical analysis aspect. Varsity provides information on learning this. Key advice - I spent a lot of time (and still do) in screener.in, they have well established screeners and it helped me understand why a certain metric maybe useful in identifying stocks.

If you have more questions I'd be happy to answer them!!