Click-lock luxury vinyl plank is the most forgiving DIY floor on the market. The planks float on top of your existing subfloor, the tongue-and-groove edges snap together without glue or nails, and you can cut most pieces with a utility knife. A laundry room takes one afternoon. A whole bedroom is a weekend if you take your time.
Before you open a box of planks, give them 48 to 72 hours in the room where you're installing them. Vinyl expands and contracts with temperature and humidity, and an acclimated plank locks tight and stays tight. While you're waiting, run a moisture meter across the subfloor in a few spots - anything above 4 percent and you need to dry out the room or pull the subfloor up. Leave a quarter-inch expansion gap around every wall and fixed object so the floor has room to move once it's down.
This walkthrough is for a click-lock LVP install over an existing sheet vinyl subfloor. The same steps work over plywood, OSB, tile, or concrete - the prep changes a little, but the install sequence is identical. Related home-improvement reads: how to install laminate flooring uses the same click-lock mechanic with a slightly stiffer plank, and how to fix holes in drywall covers any baseboard damage you find when you pull the shoe molding.
Tools you'll buy if you don't already own them: a vinyl plank cutter or sharp utility knife, a tapping block, a pull bar, and a bag of wedge spacers. A circular saw or jigsaw handles the cuts you can't score-and-snap. None of it is expensive and you'll use most of it again on the next flooring job.