learning cycles

NSE:NIFTY   Nifty 50 Index
my hello world attempt on mapping cycles with Nifty

i see 4 short term to medium term cycles at play

3 month
6 month
18 month
4.5 years

Ideally for day to day, 3 month cycle has more weight , followed by 6 month.... and so on but their amplitude is other way around

whats interesting is that 18 month cycle is decider in major changes (dips more than 10-12% at index level). Whenever 18 month cycle is on downswing aided by downswing in shorter cycles, dip is significant.

i need to figure out how to attach weight factor and amplitude impact factor to each cycle) and how to create a combined effect graph to backtest and future predict the movement.plotting these on tradingView is little cumbersome as in practical, cycles are not exact length and scales are not same but this is my first attempt. Anyeone who can guide on how to progress with this topic is welcome to comment (