As long as you are online. They can do everything for you in the download. It doesn't take long unless you are still using the OLDER, SLOWER modums with all those crazy sounds through a phone line.
WIFI, or whatever your ISP (Internet Service Provider) Speed happens to be....is adaptable for installing 10. And they do give you the option by creating a Directory for your OLD Windows 7, if you choose. It's all up to you. And yes...Microsoft has control of the installation, updates, and even the DRIVERS needed to operate 10. Since it won't be Free for long. What can you lose? And if you hate change that much. Just wait till YOU CAN'T GET ONLINE anymore because the Internet doesn't work without 10 on your machine. BUT...It's your choice. Just trying to be helpful here.