dual boot - What does the "install alongside Windows" feature do exactly?

I'm installing Ubuntu and unfortunately I haven't been able to find in detail what the "Install alongside Windows" feature will do.

Here's my configuration:

• Drive 1:
  
  
  
  • Boot partition
  
  
  • Windows partition (NTFS, 180 GB)
  
  
  • Free space (80 GB)
  
  



• Drive 2:
  
  
  
  • Data (NTFS, 250 GB)
  
  

Now, of course, I'd like to use the free space for Ubuntu mount points and everything else untouched. Will this feature touch any of my other drives or partitions?

It will use the "unallocated"/"free space" partition. In this case the 80Gb one.

When in doubt opt for the manual option.