Bearish calendar spread using futures

My question is how to execute this strategy

Did I do it right ? ( Because in SENSIBULL payoff graph it shows totally different )

or is it the other way around long the near term futures contract and short the longer term futures contract

Could some one clarify ???

Generally, it is tough to find an arbitrage opportunity in such scenarios. Assuming your view is bullish, considering the higher qty in July future,

One scenario which can lead to profits is…In June, if the stock falls, the june month futures may correct more than July purely considering to Time to expiry, Interest rate factor.

Any particular reason why you felt there is an arbitrage opportunity in this case?

I was bearish ; Lot size changed with JULY series
Exited now