To understand beta, refer Investopedia link: https://www.investopedia.com/terms/b/bet...
A beta value of 1 means the stock is directly correlated to benchmark index - would be same as overall market.
Beta value less than 1 and greater than 0 means the stock is less volatile than the market.
Beta value more than 1 would mean the stock is more volatile than the market.
A beta value of 1.2 would roughly translate to the stock being 20% more volatile than the overall market.
A negative beta value indicates the stock is inversely correlated to market.
In the example chart, you can see the Beta value change in NSE:RELIANCE with respect to NSE:NIFTY.