The wording might be different, but yes, something like that. When you deposit funds to the exchange, they get deposited to a main/primary wallet. Let's say you deposited BTC. If you open any trading pair with BTC, the exchange will show you that you have no funds in your account even though you made a deposit. But to be able to trade, you need to go into your exchange wallet and move the coins from your primary account to your trading/swaps account. The usual password/PIN/2FA might be required. Only after you do that, the correct balance will show up when you want to exchange BTC for some other coin.

It's similar to when you want to withdraw from the exchange to your personal wallet. If the coins are still in the trading/swaps account, and there is nothing in the primary wallet, the exchange will show you a 0 withdrawable balance. The funds have to be transferred to the main account so you can withdraw them from there.