As long as you are inserting your synth via the browser you will always see the, "insert synth options" screen before anything else happens.
Here you have a range of choices. I tend to always use the same options (I never use "simple instrument track")
The options are fairly self explanatory such as, Midi source means you will be given a single midi track that will already be assigned to your instrument.
Synth track folder is always useful especially when you have a multi instrument synth that is being fed by multiple midi tracks with multiple audio outputs
which is what you will be using. Ticking, "include midi track" doesn't mean you cant add further midi tracks, it just gets you started.
If you are only going to be using one synth with one midi track then you should choose, "first synth audio output" otherwise you can choose whether you
want to have stereo or mono outputs.
Hope that's helped
Steve