I assume this reflects the back of your actual switcher.
Since there is NO provision for a 3rd TV...you will use the output labled TO VCR for your TV #3. The Output cables "To TV1 and To TV2 should be wired to the cable input nipples on TV's 1&2 with the output cable from "ToVCR wired to the cable nipple on TV#3.
You should wire your antenna cable to the nipple on the box labled "FROM ANT" and your cable connector wire to the nipple on the box Labled FROM AUX.
Based on your description, the ONLY nipple on the box that should be left open is the one labled FROM VCR.
When you have it all wired up...the buttons on the front for VCR will not do anything. The middle TWO buttons for ANT & AUX for the VCR will actually control what your TV#3 gets. The other sets of 3 buttons on the left and right will control what TV#1 and TV#2 gets respectively.
Hope this helps.