Installation: By far the easiest way to install this software is to go to use the following link. You will need to register, but it is free. This is serious professional software, not some watered down educational junk. Be warned the full package is nearly 14.2 gigabyte installed!
For instructions visit: http://www.nhn.ou.edu/~bumm/ELAB/DigiLab_software.html
Recall that you can also come into the ELAB and use one of the Elab Laptops.
Please see this site for the example to familiarlize you with the design flow in Vivado. You will load the files of an existing project, generate two different types of programming files (*.bit and *.bin), and program your Basys3. [link here]
Example VHDL code for lab15 problem 4a. Demonstrating implementaion of a logical expression.[link]
Example VHDL code for lab15 problem 5. Demonstrating hierarchical programming in VHDL. [link]
For reference: Select Device
product category: General Purpose
package : cpg236
Temp grade: All Renaining
Choose frm the remaining devices: xc7a35tcpg236-1
For reference: Select Configuration Memory Part
You can access these setting afetr you Open Implement Design
From the Tools menue, select Edit Device Propoerties
General : Enable Bitstream Compression [TRUE]
Configuration: Configuration Rate (Mhz) 
Configuration Modes: check the box [Master SPI x4]
Then from the Hardware Manager. Right click on the FPGA [xc7a35t_0]. Select Hardware Device Properties from the menu that pops up and select the flash memory chip.
Debsity (Mb): 32
Choose from the remaining devices: s25fl032p-spi-x1_x2_x4