See if this helps
How to Create a Bootable USB Flash Drive to Install Windows 10
However isn't your Win7 computer able to upgrade to Windows 10 already?
The above link will give you the information based on some selections to choose from but why not use the Windows 7 upgrade feature?
See How to upgrade to Windows 10 step : To Upgrade to your Reserved Free Windows 10 from Get Windows 10 (GWX) app
Compare them and see which one you can follow: post back for any questions and concerns
Before you do so create a Windows 7 system image backup & a system repair disc or use a 3rd part program
Also back up your data
When you do upgrade to Windows 10 do not make any immediate changes
Use it for a day or two
If you like it, create a system image backup
Then if you need to add some programs, apps, user accounts etc. go ahead
Know that if for some reason you will prefer to revert back to Windows 7, it is possible but depending on some factors sometimes it doesn't work one of those factors being some additional items that have been added: that's the reason I recommend the "pristine" image backup: the idea to revert back to Windows 10 is reverting what has been originally upgraded
With all of that said, I like Windows 10 and see it as a great upgrade so I hope I'm not being alarmist to you.