Installing hardwood flooring or cap atread on stairs involves a series of steps to ensure a secure and aesthetically pleasing result. Here's a step-by-step guide:

1. Preparation: Remove any existing flooring, such as carpet or laminate, from the stairs. Clean the stairs thoroughly to ensure there's no debris or dust. Measure each stair tread and riser accurately.
2. Gather Materials: You'll need hardwood flooring planks, construction adhesive suitable for hardwood, nails or screws, a saw (preferably a miter saw), a drill/driver, wood filler, sandpaper, stain, and finish.
3. Cutting the Treads and Risers: Cut the hardwood flooring planks to the dimensions of each stair tread and riser. Make precise cuts, ensuring a snug fit. You may need to cut stair nosing for the front edge of each tread.
4. Install Risers: Start by installing the risers. Apply construction adhesive to the back of each riser and press it firmly against the stair riser. Secure the risers in place using nails or screws, making sure they're flush with the surface.
5. Install Treads: Apply construction adhesive to the stair tread and place it on the stair, starting from the bottom and working your way up. Secure the treads with nails or screws, making sure to countersink them. Use stair gauges to ensure consistent overhang on each tread.
6. Finishing Touches: Fill any nail holes or gaps with wood filler. Sand the entire staircase to smooth out any rough edges and ensure a uniform surface. Stain and finish the stairs according to your preference, allowing each coat to dry completely.
7. Install Trim and Molding: Install trim or molding along the edges of the stairs to cover any gaps and provide a finished look. Ensure the trim matches the hardwood flooring for a cohesive appearance.
8. Safety Considerations: Add non-slip stair treads or adhesive strips to enhance safety. Ensure the stairs comply with building codes regarding tread depth, riser height, and handrail installation.

Regular Maintenance: Clean the hardwood stairs regularly with a hardwood floor cleaner and avoid excessive moisture.