How I use the drive I create to make it usable to download there?

In Linux, other partitions are not automatically connected to the system unless the administrator sets that up. The exception is external drives that you plug in into USB. These are automatically mounted for the current user.

Permanently mounting a partition

You therefore will need to set up that partition that contains your Download location to automount during startup. This can be done using the tool "Disks" (command: gnome-disks).

1. In the tool, select the partition you want to mount automatically during startup.
2. Click the cog wheel and select "Edit mount options".
3. In the "Mount Options" dialog that appears, disable "Use session defaults"
4. Check the option "Mount at system startup"
5. A generic mount point under /mnt is proposed by the tool. You can leave this as is, but you also could choose your own folder where you create the mount, e.g. /mnt/Downloads or it could even be the Downloads folder in your home folder (/home/<yourlogin>/Downloads) if you exclusively use the partition for downloads..
6. Click "OK" when done. The Disks tool will include the partition in the configuration file /etc/fstab. Check also that it creates the mount point, i.e., the folder where the partitioning will be accessible. If not, create the mount point you specified yourself.

Making the partition readily available under your home folder

Your desktop by default comes with a "Downloads" folder. You can conveniently change that folder by a symbolic link to the other partition, and thus conveniently continue to use Downloads in your home folder to immediately have them on the other partition.

By default, you will not be able to write as a normal user on the newly mounted partition. So create a Downloads folder there as administrator, and then change the owner of that folder to your user.

1. Open the file manager with administrator ("root") power: Hit Alt+F2, then enter the command nautilus admin:/// to open a Files window that has root priviledges (be carefull!).
2. Navigate into /mnt and create a folder "Downloads".
3. Change the owner of that folder from root to your own user: right-click, properties, "Permissions" tab. Just change the owner using the drop down: it immediately is changed.

Close the Files window now. You continue as regular user. Now create a symbolic link:

1. Open two nautilus windows side by side. Open the left one in the /mnt folder (you get there via "Other locations" in the left bar). Open the right one in your home folder.
2. Delete the current "Downloads" folder in your home folder.
3. Create the symbolic link: hold Ctrl+Shift down, then drag the folder to your home folder and release it. That gives you a symbolic link. You see that by the arrow included in the icon. That link, for practical purposes, acts and behaves as a regular folder. This is an extremely lengthy explanation, only valid for the Gnome Desktop (i.e., not for other desktops such as XFCE, KDE, etc.). That is why linux users prefer to give instructions on the terminal: these work on any linux system, it is way shorter and less error prone.

With the command line, you create that link as:

sudo mkdir /mnt/Downloads
sudo chown $USER:$USER /mnt/Downloads
rm ~/Downloads
ln -s /mnt/Downloads ~/Downloads

That is all.

To change the permission do this in terminal (substitute username/groupname):

sudo chown username /media/andres/varios

if you want to set the group as well use

sudo chown username:groupname /media/andres/varios

For automatic mount on boot have a look at the

/etc/fstab

file and how it's used. Have a look into https://help.ubuntu.com/community/Fstab