I am unfamiliar with the GST portal. Can you guide me on how to download the returns and upload returns by using BUSY?

For downloading GSTR returns you need to follow these steps
 Step 1:Go to administration menu and select configuration from it.
 Step 2:After that select feature and option and then select GST/VAT tab.
 Step 3:In GST/VAT window make sure you have mentioned correct GSTIN and GST portal username.
 Step 4:After that login your GST portal and Go to your Return dashboard.
 Step 5:Click on MY PROFILE button at right hand side on top menu and in next window Go to manage API access.
 Step 6:And then select yes on enable API request and make sure to select 30 days duration from dropdown list.
 Step 7:Then Click on confirm button to save.
 Step 8:Go to transactions menu and select GST misc. utiilties option.
 Step 9:Then click on download GSTR json data and downlaod return according to your need.
 Steps to download json file and excel template from BUSY to upload it on government portal.
 Step 1:Go to display menu and select GST reports option.
 Step 2:Then select GST Returns option.
 Step 3:After that select the GST return which you want to export and select the format json or excel template.
 Step 4:Then specify the period and check possible errors in the specified period.
 Step 5:Lastly click on proceed with json or excel as the case may be.