wordpress could not create directory

[admin]

Good day folks,
I was trying to update my wordpress site and i have this error:

<blockquote>
Unpacking the update… Could not create directory. Installation Failed
</blockquote>

After googling, i have found a solution that says:

<ol>
<li>Web Server Ownership

The first level is actually to make sure that your web server has ownership over the directories:

chown -R www-data:www-data your-wordpress-directory

</li>
<li>Directory Permissions

The second level is also required – you must make sure that the directory permissions are properly set:

sudo find /var/www/wordpress/ -type d -exec chmod 755 {} \;
sudo find /var/www/wordpress/ -type f -exec chmod 644 {} \;

</li>
</ol>

Could anyone guide me how to perform those tasks?

Regards