I'm quite a novice in SharePoint development (but not new to programming ;-)) My question is: Where to install Visual Studio 2012 Prof. ? On the server on which ShP 2013 is installed? On my local machine? How to connect to SharePoint then? Thank you very much!
Needing Visual Studio for SharePoint development depends on the type of development you are planning on doing. If you are planning on server side code (.NET) or using things like Sandbox solutions or Visual Studio workflows, then you'll need to install Visual Studio on a SharePoint server.
If you are wanting to do SharePoint Designer workflows or to develop client-side solutions without packaging, then you don't need Visual Studio at all. You can use SharePoint Designer instead. SharePoint Designer can be installed on your machine.
If you are installing Visual Studio, then this should be done on a development server. Often this is a Virtual Machine (actually machines since you'll need a full environment) or an Azure based farm. Sometimes, you may even have a development farm to be shared across developers (not very common). The key thing is to NOT install Visual Studio on your production server.