GSTR-3B report

When to use this: review the outward-supplies figures for a GSTR-3B period with your accountant.

Steps

Open Reports → GSTR-3B. Click Reports in the left menu, then click GSTR-3B from the list of reports (on a wide screen it opens under Reports; on a smaller window it's a column on the left of the page).
Pick the period. Set From and To at the top right. The report reloads when the dates change; use Refresh to load it again.
Read the Outward Supplies tab. This is the first tab. It shows six summary cards: Taxable Value, CGST, SGST, IGST, Total Tax, and Total Invoices, for the period you picked.

1 sets or refreshes the period, 2 selects Outward Supplies, 3 shows the six totals, and 4 exports this tab.
Switch to Rate Slabs. The table breaks sales down by place of supply, supply type and GST rate. It shows taxable value, CGST, SGST, IGST and invoice count, followed by a TOTAL row.

1 selects Rate Slabs, 2 shows the breakdown, 3 totals the values, and 4 exports this tab.
Export for review. Each tab has Export CSV, Export Excel and Export PDF buttons. Choose the format for the tab you're viewing.

This BitMed report shows outward supplies (sales). It does not include purchase-side input tax credit; review the remaining GSTR-3B sections separately.
Fix data problems at the source (tax review, voids/returns done properly) — never by editing the exported file.