How do I predict Macroeconomic indicators?Or are there any free resources where I can get the predicted values?
I will give a partial answer.

I assume you mean “forecast values.” Forecasts generally come from private firms that do the forecasts, and are typically expensive. There are some surveys that are in the public domain (Philadelphia Fed Survey of Professional Forecasters). You can generate your own using a model, but quality depends uponyour model.
It is normally easier to work with seasonally adjusted data. However, the data are passed through a filter, and distortions can occur. (For example, the pandemic of 2020 has caused spikes in data, and seasonal adjustment can make those spikes worse.)
The last question is open-ended. People spend their entire careers in finance and at central banks building models.