How to d procedure gst registered turnover

a small business person
gst registered before sales turnover
rs:10 lacs(from 01-04-20 to 31-08-20)
gst registered after sales turnover rs:25 lacs(from 01-09-20 to 31-03-21)
total sales turnover declared rs:35 lacs in f.y.20-21 show in it returns
question:
dealer gst registered before sales turnover how the show procedure in gst returns in f.y 20-21.
dealer composite tax pay turnover on rs:25 lacs only.