How to access other levels on destiny

I completed the first mission im rank 2 on the game, l go to the tower and it still doesn't work, please can any of you guys help me


After completing the first quest, you'll be able to pick your next missions from the Explorer. You can only select new missions by going to orbit. From there you'll see a Select Destination button: destiny orbit

And clicking on that will show you:

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Selecting a planet or activity type will give you mission and activity options.