Automatically mount partitions in Linux Lite

[Moltke]

I've made the partitions during installation, there is no other OS, no dual boot or anything

You probably made something wrong when partitioning.

I will try installing it again, deleting all the partition and letting the entire 500Gb HDD to install on, then to make the partitions with gparted.

When installing, just choose the defaults "erase disk and install Linux Lite" and once LL's installed do the partitions you need.