This is commonly done, but depending on your soil, the wood will last only a couple of years before it starts to rot. When you have to remove the post, it's a lot harder when there is concrete around it. If you want a post that will last for about 10 years, use treated wood, and cover the underground part with roofing tar. You can set the post as soon as the tar hardens. Also it is a good idea to cover the above ground portion with a couple of coats of linseed oil, so that the treatment chemicals (which are water soluble) do not get washed away from the wood and do not get into the run-off water going into a stream. Wear a tight-fitting dust mask when sawing the wood, because the chemicals are not good for you. For a post that will last for 20 years, you can drill holes in the bottom of the post, about two feet long, then insert stainless steel heavy-wall pipe. Put a 1/4" steel cap on top of the post, then pound it into the ground with a sledge hammer. After you have it in so the pipes are a couple of inches or more above the soil level, pour concrete around the pipes. I built a form for the concrete out of Hardibacker.
For expert advice on building wood decks and sun shades, visit www.finehomebuilding.com and search through the old articles. The latest edition of Fine Homebuilding (May 2019) contains several articles about decks. The details are critical. An outdoor wooden structure has to be designed so water does not collect anywhere in the structure.
The two pieces I bought were not bundled.
Best to check with a qualified engineer when working with load bearing members. The Western Wood Products Association ( https://www.wwpa.org/ ) has a link to download design information for Western softwood lumber.