I might add my 2 cents worth here. Get the right chemicals to do the job right. X-13 Gutter Gernade is what you want to make those gutters look like new, about a 15:1 ratio. It doesn't take much. Spray it on in the shade and rinse before it dries. You won't believe the difference. On vinyl houses I coat them with a light bleach mixture and use a FatBoy to pump it from chemical tanks in the truck. Dwell for 10 minutes and rinse. You can use an XJet for this too. DO NOT buy an extension wand. Years ago when I first tried the XJet I came home and used a chain saw on my extension wand so it would fit in the trashcan. I also mix Simple Cherry to keep things rinsing well. Lastly, do not rely on pressure to clean the house, you'll only get into trouble. The key to a good job is water volume, not pressure.
Try to start at the gutters so you don't have to rinse the whole house over. A lot of nastiness is going to come off those gutters and land on the vinyl siding. Let us know how it works out.
BTW, YouTube has tons of videos but not all of them are good. Use your common sense and you'll do fine.