docs: Clarify some FAQs in the Tutorial [skip ci]

Clarifications that were observed to be needed when seeing a user try
the Tutorial for the first time at:
https://www.twitch.tv/videos/709237047?t=50m20s

docs/markdown/Tutorial.md

@@ -45,7 +45,10 @@ project('tutorial', 'c')
 executable('demo', 'main.c')
 ```
 
-That is all. We are now ready to build our application. First we need
+That is all. Note that unlike Autotools you [do not need to add any source
+headers to the list of sources](FAQ.md#do-i-need-to-add-my-headers-to-the-sources-list-like-in-autotools).
+
+We are now ready to build our application. First we need
 to initialize the build by going into the source directory and issuing
 the following commands.
 
@@ -118,6 +121,15 @@ gtkdep = dependency('gtk+-3.0')
 executable('demo', 'main.c', dependencies : gtkdep)
 ```
 
+If your app needs to use multiple libraries, you need to use separate
+[`dependency()`](Reference-manual.md#dependency) calls for each, like so:
+
+```meson
+gtkdeps = [dependency('gtk+-3.0'), dependency('gtksourceview-3.0')]
+```
+
+We don't need it for the current example.
+
 Now we are ready to build. The thing to notice is that we do *not*
 need to recreate our build directory, run any sort of magical commands
 or the like. Instead we just type the exact same command as if we were