@José, I agree with guido, I highly recommend using modules to create the changes that you require rather than just updating using the Odoo interface. There is a good book for getting started with odoo here:
https://www.packtpub.com/hardware-and-creative/working-openerp
which covers some basic module creation for v7 aimed at first time users looking to implement OpenERP 7 (ie. now Odoo 7)
as well as some online documentation here:
https://doc.odoo.com/contribute/05_developing_modules/
http://openerpbook.com/index.html
as well as some OpenERP SA documentation that is still under heavy development but may be useful found here:
https://github.com/odoo-dev/odoo/tree/designers-doc/doc
https://github.com/odoo-dev/odoo/tree/8.0-moredoc-xmo/doc
if however you have a basic idea of how to create a basic Odoo module then I suggest you split your questions into one forum post each and pose them to the community forums here. Provide as much detail as possible for what you are trying to achieve and you may find community members can offer you some suggestions on how to accomplish what you need to.
