Conversion from Sentinel-1A SLC to GRD

Could some one explain in details the workflow of converting the Sentinel-1A SLC to GRD.

The GRD is already available, you don’t need to convert anything,

Also many posts were already mentioned regarding this issue,

Please take a look at this post

And this one

To get understood the difference between SLC and GRF

I want to compare two SAR images of a same place with in a short period (better in minutes).

However, the GRD products have a temporal reosulotion of 12 days for a same scanning ‘box’!
But for SLC products, although they are also 12-days, but two successive scanning boxes (time interval just minutes) in one orbit are overlapping.

My interest region just in the overlapping area! So I want to use SLC product

So are you saying that your AOI is in the burst overlap area? Then the time interval should be some seconds (the radar is imaging the other two subswaths first, before adding the next burst in the same subswath)