When installing openSUSE just make sure uncheck the automatic setup option during the install. This will give you the option to add / configure your own partitions. Then add your openSUSE partitions after the windows one. The recovery partition is usually at the end of the disk (well that’s how it is on Thinkpads) so your partitions will go in the middle. Make sure you add at least a /boot partition as well as /home and /swap. the rest can be /.
Make sure you set GRUB to boot from the boot partition.
You should then be OK, as the dual boot will be controlled by GRUB without messing with the original windows boot record.
I have not used a s10-2 but being a Lenovo I’d assume it’s not too dis-similar to a Thinkpad and has the recovery partition which can be accessed at boot time via the blue Thinkvantage button.
If you want to preserve this as well as not mess up the Windows boot record then, yes install the oS bootloader in the /boot partition. Then when the laptop boots, you’re presented with the Grub boot menu where you can select when OS to boot.
Pressing the Thinkvantage button before the Grub boot menu will invoke the Lenovo recovery system.
The problem with allowing oS to replace the Windows boot record is that if ever you ever want to remove oS, windows will fail to boot.
That’s how it works on my Thinkpad. I found plenty of info on this and specifically an article which expalined it all in detail. Unfortunately I cannot find it at the moment but will look later when I have more time.