Hi, Salesforce newbie here. I'm trying to understand how all this Salesforce stuff fits together. Is Visualforce the old front end platform? Has it been replaced by Lightning?

I'm trying to get started with the Trailhead developer tutorial.  I'm on this page: https://trailhead.salesforce.com/trails/force_com_dev_beginner/modules/platform_dev_basics/units/platform_dev_basics_intro

Under the heading Install the DreamHouse App it says "Click the arrow next to Launch and select Create a Trailhead Playground”.  

I don’t see any arrow, or the word Launch.  Got any tips?

I'm trying to get started with the Trailhead developer tutorial.  I'm on this page: https://trailhead.salesforce.com/trails/force_com_dev_beginner/modules/platform_dev_basics/units/platform_dev_basics_intro

Under the heading Install the DreamHouse App it says "Click the arrow next to Launch and select Create a Trailhead Playground”.  

I don’t see any arrow, or the word Launch.  Got any tips?

The OOTB component for feed and feed publisher do not work unless the URL has a recordId (at least for this use case). If there is no recordId in the URL, the user is presented with a message along the lines of:  "Looks like there's a problem. We couldn't find the record you're trying to access. It may have been deleted by another user, or there may have been a system error. Ask your administrator for help."

How can I add some custom dev to this OOTB component? I know how to custom show/hide based on criteria (whether or not a recordId exists) but is that possible with OOTB components? If not, what might be a possible workaround for the time being?