How to setup boot partition-->win 7 partition?

In the early days of Win7 it was usual to install one Win7 system on a partition (say A) and let it be called during bootup from the partition independent MBR from the hard disk directly:

MBR ---> partititon "A" (with Win7)

Then it became more and more popular to install two different Win 7 systems (one work one for test/reserve) on two separate partitions (say A and B) and let the user choose at bootup in a BootManager menu which of the two should be started.
The BootManager can be put in a third, small partition (say BM with 100MB size). So the possible call chain is like:

MBR ---> partition "BM" (with BootManager) ---> partition "A" (with first Win7)
or
MBR ---> partition "BM" (with BootManager) ---> partition "B" (with second Win7)

Ok, I know how to install a Win 7 on a partition.

1.) But how do I tell which software: "Hey, put a Boot Manager on small partition BM and call this from MBR.
Then in BootManager link to all (=both) existing real, full Win 7 installations on partition A and B)"

2.) Can I do this from within one of the two running Win 7 systems or do I need another software for setup?

3.9 Do I have to install both Win 7 systems at FIRST before BootManager or can I install and add additional Win 7 systems later to BootManager menu?

Peter

It is the same as dual boot Windows 7 & Windows 8.
Dual Boot Installation - Windows 8 and Windows 7 or Vista
Setup "B"


When install second Windows 7, this install will make BootManager menu.

The second Win7 install should configure a Dual Boot menu. If not you can install EasyBCD (click Download - no Name or Email required) to add the other OS on the Add OS Entry tab. You can also change the name of an existing OS on the Boot Menu from the Edit OS Menu tab>Rename.