How to put IE into background so it will not run concurrently with Firefox yet have it ready if want

Not sure I understand your question.

You can have both installed on your computer at the same time. Whether they run concurrently or not depends on if you start them at the same time or not.

You can view the web in Firefox, or IE, or both at the same time without issues.

How to put IE into background so it will not run concurrently with Firefox yet have it ready if wanted?microsoft office

Firefox has an add-on that allows you to open a tab in IE, but still be in the Firefox browser. It will put an IE tab on your Firefox tab toolbar.