A person is out walking at night, completely alone, and ends up in a conversation with themselves. That's the whole scene, and the poem keeps it just as small. The title, "Soliloquizing," names the habit of speaking one's thoughts aloud, usually when no one else is there to hear.
What makes the poem interesting is the quiet oddity in the middle line: "I answer myself." Talking to yourself is one thing, but answering means there are two sides, a part that asks and a part that replies. The speaker is both company and companion.
The mood is hushed and a little wistful. Loneliness is there, in "all alone," but it doesn't feel desperate. The speaker seems fairly at ease, even gently amused by the habit. The night setting adds stillness and privacy, a place where no one is listening and it's safe to think out loud. The short, plain lines mimic the rhythm of footsteps, one small thought after another.