How to use 2 partition on HDD box

I created two partitions sda1 and sda2 for my HDD box. Now I want to use the sda1 partition as the overlay memory for the router and the sda2 partition as the local LAN file share partition. How do I do it? I followed these two videos but there was an error when I used the ntfs-3g package. my router cannot mount sda2 partition