You have a couple of different options - and even though some of what Leon says is correct, it's confusing. So let me try to clarify things a bit.
There are two ways to apply for spousal PR - the
inland application process (which happens entirely in Canada and would require you both to be in Canada during the 12-18 months it takes to finalize it) or the
outland application which would be processed at the Canadian embassy in Berlin. Because your husband is a Canadian citizen, he can apply to sponsor you while residing abroad with you, but he needs to be able to demonstrate to Immigration Canada that he will accompany you and re-settle in Canada once your PR is approved. Normally the outland process is faster, but Berlin is currently finalizing spousal PR applications in 6-13 months - which isn't that great if he needs to get back to Canada sooner rather than later. However, because Germany is a visa-exempt country, you do not need to apply for a visitor visa to come to Canada, and it's possible for you (even with an outland application in process) to come to Canada with your husband and son and stay here as a visitor until your outland ap is finalized. The drawbacks to that are that you will have to travel to Berlin if an interview is required (that usually happens earlier on in the process), and you will have to get your passport back to Berlin once your PR has been approved - which, if you don't feel it's safe to mail it and stay in Canada without it, would mean another trip to Berlin at the end . . . after which you come back to Canada and "land".
The other option is to file an inland application once you are successfully in Canada. The inland process takes 12-18 months to finalize, but you can reach first stage approval within 4-5 months. The key to filing inland is getting the application in before your temporary status in Canada expires (typically 6 months for a visa-exempt national) and filing a
temporary status extension application in the same envelope with the PR application. This protects your temporary status until a decision is made on first stage approval, and if you check "Initial Work Permit" on the extension ap, you'll be issued an open work permit at that time. The biggest drawback to an inland ap is that there is no right of appeal if the file is refused - so if you have any "issues", think carefully about using it.
Either way - getting into Canada as a foreign national married to a Canadian citizen needs to be done properly. There are instructions for how to accomplish entry for visa-exempt (only) nationals who want to stay in Canada with their spouses
at this link. It will explain the differences between entry for visa-exempt nationals and those who require visitor visas. Then read carefully the information at the "Visitor Record" link provided on the page.
