Hi everyone, GF and I wanna invest in a pop up for camping next year and I'm trying to do some research and something I miss

First our car is a Kia Sedona 2020 that seem to have 3500 pound tow rate

On Uhaul website they can sell and install the whole kit from the Hitch to the wiring for 450$ CDN tax in installed. but they seem to have 4 pin wiring only

From what I heard 7 pins is only good if the pop up has Electric Breaks and a 12V battery

So my questions are

1) WTF is electric Break for a pop up
2) If I want 7 pin am I obligated to install 4 pin at first then at some other place upgrade to 7 pin?
3) Other wise can I just install a 4Pin wiring and then get an adaptor like this one to convert to 7 pin?


4) If I do get a 7 pin wiring, I'm guessing I'll need another adapter incase I wanna use a normal trailer as they are 4 pin only?

5) the 3500 pounds I heard to use max 80% of it so about 2800 pounds, I'm guessing this count, the pop up, the stuff inside, the stuff inside the car and the passenger weight?

Thanks all