And now i want to install windows 10 on one partition.
To my experience Win10 is difficult to handle especially if you run an "Acer" hardware. I was able to do with ease installing (after Linux) a Windows 8 and/or 7. Better consider this factor. However, if you run a real brand open-minded hardware you may get the chance with Win10.
can i please have some guidance how to do it step by step, because i ve heard that windows doesnt allow booting up of other operating systems when it is installed after linux.
I backed up everything first, especially the MBR and/or the UEFI partition, because these things go away at windows 10 install.
After installation you only need to run a linux liveCD (or Gparted or any repair liveCD whatever you have) and restore the MBR or the first partition, chroot into the partition originally running your grub then issue the following grub commands:
/usr/sbin/grub-set-default <your current grub partition> and
This time grub should be able to see the newly installed win10 and offer to boot into it. Before doing anything please get yourself familiar with Grub first, read this good tutorial
Hope that helps. Good luck and enjoy.