after compiling and analyzing the code a window will pop up and there you must click on "Open implementation design" it may directly bring you to the I/O planing. If not, at the bottom of the page click on the "I/O ports" tag and assign pins there. After assigning I/O pins I usually again synthesize the code and this time, after synthesizing and compiling, i select "generate bit stream".
finally when bit stream generates, open hardware manager and program the code.
It is better to connect your programmer before running the Vivado. sometimes it can not recognize.