Hi guys. I have googled this question and some people have asked questions before about booking through unitedairlines to use air Canada, but I haven't seen any for multiflights even when I put it in the search. So I thought I'd ask here.

So I'm going to the US from the UK through united airline. I have been given my seats for my two flights to my destination (UK > layover > destination) but when I'm flying back it's through Canada so united booked me through them but I haven't been given my seat numbers. Will I be given this information when I go to the airport in UK to get my boarding passes for united airlines? Or will this be something I need to go ask around at the help desks once I'm in American and wanting to come back home? If this comes across as a dumb question apologies. Now that I'm getting closer to flying solo I'm getting more freaked out.