Zetech University is located in Ruiru along Thika Road. You will not enter Ruiru town, but alight at Ruiru footbridge/flyover.
The primary option is to board the buses going to Ruiru or Juja. They include Lopha Travelers and Runa Sacco, available at the intersection of Ronald Ngala St and Munyu Rd, just next to Virginia and Nicco buses. Tell the conductor to drop you at Zetech University. Inform him or her in advance.
Kenya Mpya, Lothian, and Super Metro buses plying Nairobi-Thika route are secondary options. Again, tell the conductor to drop you at Zetech in advance.