From the register, use New entry → Deposit.
The category dropdown is fiscal-year-aware
The list of categories you can pick is filtered to the fiscal year of the deposit date. Change the date and the dropdown refreshes — useful if you’re back-dating a deposit into last fiscal year and need its categories, or if you just added a new category and need to nudge the dropdown to pick it up.
Saving creates one ledger entry, not one per split
Every deposit is exactly one entry in the register, regardless of how many splits it has. Clicking into it on the detail page shows the splits broken out.