How to download videos on instagram?

I don't understand at all how some people download videos to instagram. I've tried to find something like this on the internet, but I can't get it to work. Do you have any tips?

Pandora Jewelry
Pandora Charms
Pandora Charms
Travis Scott Jordan 1
Air Jordans
Jordan 11s
Jordan 11
Jordans Shoes
Moncler Outlet
Off-White
Yeezy 450
Yeezy 500
Nike Outlet
Jordans 4
Jordan Retro 4
Jordan Shoes
Yeezy
Yeezy 700
Yeezy Supply
Off White Shoes
NFL Jerseys
Retro Jordans
Nike Air Jordan
Jordan Shoes
Jordans Shoes
Yeezy 350 V2
Adidas Yeezy
Yeezy
Yeezy 700
Nike Outlet
Yeezy Shoes
Yeezy Foam Runner
Nike Outlet
Nike Outlet
AJ1
UNC Jordan 1
Jordan 13
Jordan AJ 1
Yeezy Supply
Yeezy Zebra
Jordan 5
Jordan 1 Low
Air Jordans
Pandora Charms
Adidas UK
Nike Store
Adidas Yeezy Official Website
Yeezy 350
Jordan 1
Nike Outlet
YEEZY SUPPLY
Pandora Charms
Nike Shoes
Nike Outlet
Pandora Jewelry
Pandora Outlet
Jordan Shoes
Air Jordan 4
Pandora Charms
Adidas Yeezy
Air Jordan 11
Air Jordan 1
Nike Jordans
Jordan 1s
Pandora UK
Nike Jordan 1
Jordan 1
Yeezy Slides
Nike Air VaporMax
Nike Vapormax Flyknit
Air Jordan 1 Mid
Adidas yeezy
Adidas Yeezy
Yeezy 350
Nike Shoes
Nike Outlet
Yeezy
NFL Shop Official Online Store
Nike UK
Yeezy
Yeezy 350