installing with existing OS on disk
 

i am trying to follow the installation wiki to install arch but i want to be sure i don't mess my other existing partitions. when i get to the part "mount the partitions" it says /mnt /mnt/boot /mnt/hom. i assume it means mkdir not mount because the etc/fstab is empty at this point and can't mount my /dev/sda3 which is the partition i want as / for arch. so do i "mkdir -p /dev/sda3/mnt/boot" and mkdir /dev/sda3/mnt/home". basically how do i mount the root partition on/mnt if i want to install on /dev/sda3. sorry if this is a dumb question i just don't want to use trial and error because i'm in the middle of a semester and don't want to lose my main os (my data is backe up but still). also can i skip all the grub stuff and just grub-update from my mint os or should i still install grub in /boot.

In hind sight I realize this was a stupid question. Mount /Dev/sda3 /mnt. I didn't realize this is what it meant. Anyway alls good now.

Note that

is different to

But well done for solving your own problem :)

Your right I didn't notice. My stupid android keyboard always puts in its 2 cents when I type.