Hello...Im new to VF pages so am struggling to create one.  I have a custom object called Client Preferences which is related to Cases.  What I need to do is capture that the user opened/viewed the related client prefernce record.  I have a field on Client Preferences  called Contact "CP viewed by".  This field is not visible to users.  What I want to do is create a VF page that sits on the Case page.  It adds the name of user who viewed the Client Prefernce record into the Contact CP viewed by field. I can add the VF page to the case, but cant get the VF page to capture what I need.   It seems easy enough but I cant get it to work.  

Created new developer org, but not understanding how to enable lightning experience.?

I'm following a Trailhead excerise in creating a custom object. In the tutorial it advices to create a help page for the custom object. The action to carry out is:

From Setup, enter Visualforce Pages in the Quick Find box, then select Visualforce Pages.

However, when I type Visualforce into the setup > search box nothing appears. 

I did a search on these forums and it seems I need to enable developer mode, so I followed a link to v34 of the Visualforce guide which has a step by step guide on how to enable developer mode. Incidentally this guide is badly out of date as none of the links in any of the steps are correct. I messed around and eventually found the screen in which I could activate developer mode. Saved. 

I still cannot see Visualforce in Settings > Search.  What am I doing wrong?

Thanks in advance.