How to start selecting stocks?

I have new to the stock market and recently(6 months ago) started investing in both index funds and stocks. In index funds I can’t do much so started the SIP and sometimes I buy the dip accoding to my risk appetite, but for stocks my portfolio is down by more than 20% as I had entered in wrong timings and bought at premium, so I stopped investing in stocks as ai had a feeling like i need to know more about this. My question is how can I select companies to invest in rest depends on fundamental and technical analysis but I am stuck at selecting companies as there are more than 4000+ companies in Nifty so going through each company is not possible then how can I find companies to start for analysing?