1. You can directly use the UART component for PSoC devices and transmit data according to the requirement. PSoC creator is the primary development environment for PSoC devices and you can find code examples related to UART to get started.
2. In PSoC creator, navigate to Workspace Explorer-> Design Wide resources-> Pins. You can assign pins related to the components added in the top design here. An ADC component can be added in the top design and the data can be sent over UART. You can find code examples for ADC as well as UART. This can be used as a base for your code development.
3. Depending on the communication protocol, this can be configured. PSoC supports UART, I2C, SPI and certain devices support BLE, CAN and LIN as well. So, based on your requirement, the appropriate communication protocol can be selected.
Thanks and regards