Welcome in the forum!
There are components made out of UDBs and others that use fixed function blocks. So when using the latter for your project all you want to have may fit into the design.
And Yes, you need to place and wire your hardware and additionally program the hardware using C-language and the provided APIs.
Can you use the SCB-based UART instead of the UDB-based one?
you have run out of UDB's; you can also use the Software Only Tx-UART component for sending data out. Works fine if CPU is not overloaded by other tasks.