Oliver,
You're in for a real treat, so just be patient.
You should definitely get the lockstrip tool and they're not always easy to find. I used dishwashing soap to help make it a bit easier. Take your time and take a lot of breaks. My second window took half the time of the first one as you start to get the hang of it. I agree with Donna and used the windshield black caulk, wouldn't use silicone anywhere on these trailers.