The parking lots used for labs and meetings would be lots I and J.
There is a Hamilton city bus stop on Main Street (Main & Emerson) right in front of ETB.
#1, #5, and #10 Bus stop here. Google Map would be the best routing tool.
When driving to ETB from Main Street, you must go down Cooter Dr then enter the campus and park in parking lot I as shown
The Go Bus stops are in the Ground Level (one level down from arrival/luggage claims) in Terminal 1. There is an inter-terminal tram between T3 and T1.
The Bus to Hamilton is #40 and its stop is near Q2 (markings on the column). Please make sure the sign of the stop and the top of the Bus says “Hamilton Go”. The other direction of #40 is to “Richmond Hill”, which is NOT what you want to take. You can buy tickets ahead of time online or at the Bus Stop (a green ticket machine on the Ground level inside the building near the Bus stop: Yellow area in the map) or from the driver.
The bus has a luggage holding bay for large pieces. The driver will help you with them.
The Bus frequency is 20 minutes during daytime peak hours and every hour during off-peak time. You can check the schedule using Google Maps or on Go Transit's web site.
You can take the #16 Go Bus from Toronto Union to Hamilton. The stop and bus connections are the same as above.