Questions about patches : how do they work ?

Being pleased with 2009 and looking for a new challenge, i am tempted to d/l patch 3.1 as there should be new database updates compared to what i currently have. But i know nothing and a friend did everything for me so far. I tried to find information on the forum but i couldnt. Here are my questions:

How do you install it once downloaded ? Do you double click on it, or do you copy paste it in a specific folder ?

Once installed is it possible to choose which database to start a season with (like there is "default" when you start a game so i guess choice is offered ?) ? Otherwise, would it be possible to come back to the previous version we had in case i m unhappy with the new one ? For instance maybe by deleting the downloaded file, or re installing the previous patch above the new one ?

Could i find somewhere feedbacks (good or bad) on the different patches ?

I'm very happy with my current version so i will wait for your answers to do it^. Thanks for your help

The 9.3.1 patch does not have any database or match engine changes and is purely a patch to get round the activation issues.

Some patches have a database update but most are bug fixes only

You will need to check the patch info for each patch to get full details of what is covered.

Download the patch to your desktop, close the game then click on the patch icon and it will self install and overwrite and problem or updated files. Once installed, you cannot go back directly to a previos version- you require to uninstall and start again. Save games in an old version will work on a newer version but save games on a new version will not work on an older version.

When you start a new game, if you choose not to use the wizard that takes you through all the steps, you are given the choice of which database you want to select.