Here's what you need to think about:
Under normal circumstances, odd-numbered pages are on the right (recto) and even-numbered pages are on the left (verso).
Facing pages start on the left so typically have even numbers. While InDesign honors this long-established printing convention, it will allow you to start page 1 on the left side with a couple of steps. It is NOT recommended if you plan to pass your document onto a commercial printer; you may get flack.
Now that you've been forewarned, here's how you do it.
Start a new facing page document with six pages (a six-page document is also strange) starting at page 2. Once the document is created, go to the Pages Panel, select all pages, and uncheck Allow Selected Spread to Shuffle. You should see brackets around the page numbers like this: [2-3]. Next, select page 2 in the Pages Panel, go to Numbering & Section Options…, change the start page to 1, and click OK. The bracketed numbers will change to 1-2, 3-4, and 5-6.
The alternative way is to set up a six-page document with non-facing pages starting at page 1, uncheck Document Pages to Shuffle, and drag the pages into “facing” positions using the Pages Panel. These aren't really facing pages, however, so margins and features referencing facing pages are likely to get a bit weird.