我做大韩航空的飞机到多伦多，再从多伦多转机到哈里法克斯请问在一个航站楼吗？

你到多伦多是KE073的航班，在T3航站楼，多伦多去哈里法克斯是AC是T1航站楼。
用不着紧张六个小时肯定是够的啦。
你到多伦多应该是免费两件的，再去哈里法克斯你只能托运一件行李的，一般在你托运的值机柜台就能交费了。记得换点加元准备交费就好了。

你未说明大韩航空航班号从何处来，也未说明离开多伦多的航空公司或航班号。所以假设离开时是 Air Canada. 并假设从大韩航空转加拿大航空是联程机票。以下是Toronto Airport Transit Information. 加拿大采用英语及法语，所以你可能看到许多标识都有两种语言，先英后法。
You'll be arriving at Toronto Pearson on Korean Air at T3, and connecting through T1 on Air Canada.
Step 1 - Arrive at Toronto Pearson
Your flight will be arriving at Terminal 3.
Step 2 - Go to Canada Customs
Follow the signs to Canada Customs.
Step 3 - Pick up your baggage
Follow the signs for the connecting carousel and pick up your baggage. You'll need to take it with you to recheck it.
Step 4 - Recheck your baggage
Drop off your baggage at the connection drop-off belt.
Step 5 - Confirm your gate number
Look for your departing flight on the flight information screens and double check that your "D" gate hasn't changed.
Step 6 - Take the LINK Bus to Terminal 1
Your connecting flight will be leaving from Terminal 1, and the quickest way to get there is the Terminal Link. The bus picks up guests 24/7 from the Departures level curb of Terminal 3 and travel time is approximately 6 minutes. Follow the D gates signs to the bus stop.
Step 7 - Go through security screening
Proceed to the "D" security screening checkpoint.
Step 8 - Head to your departure gate
There are various flight information screens throughout the terminal that will point you in the direction of your departing gate.

所有联程机票托运行李及费用都是在最初起站航空公司柜台处理。6小时转机时间太多了。还有时间可以打个盹。

建议你打电话给你买票的地方，问他们，可以得到答案。 如果不清楚就找个大的航服，先问机票情况再顺势问你的问题。会得到你要的答案的。。。