I am trying to configure my Transmission client (installed from the appstore)…to use an external HD to store the downloads.
Now my problem is that probably in the future i might remove the HD to back up some stuff from my laptop…I am not that great with linux, but from what i understood, when the pi boots, it might ‘catch’ my wifi usb stick on sda1 and my HD on sdb1 or vise versa, so i have to use a more permanent solution to be sure its always on sdb1, by using the UUID of the disk right? I also read though that sometimes if the HD is not connected to the pi, and i have it set up with this UUID that maybe the pi will get stuck on the bootup screen.
So what is the proper way to hook up an external NTFS HD (with ntfs-3g probably) to the pi2 and make sure that it will always be on a fixed ‘port’ so i can mount it and use that path in transmission config file, without worrying that if i unplug it that the pi will ‘hang’.
Confusing i know but i dont know the technical terms to say all this properly 
sda/sdb would only ever be a hard disk not a wifi adaptor so no concern there.
If you are just letting the drive automount its mount point will be based on the Volume name of the drive (or it’s UUID if it doesn’t have a Volume name) and will be constant - the only source of trouble might be if you plugged in an identically named drive.
If you are manually mounting your external drive in /etc/fstab then yes you can replace /dev/sda1 (or whatever) with UUID=f23kjn2-fwsfsf-23sdfsf or whatever your drive’s UUID is, as reported by blkid.
Thanks for clarifying this. So i dont have to do anything extra…just plug and play then…since there is no way i’ll add another HD with the same name
And will it automatically use ntfs-3g instead of normal mount ? or its better to just manually add it myself in fstab using ntfs-3g ?
I read that its better reads/writes with ntfs-3g thats why i am worrying about it.
We use ntfs-3g automatically on NTFS drives. You can check that by running the mount command.
Awesome,another thing i didnt know 
Thanks again for all the info!