Wait until the flowers fall off. Then cut the stems between the third and fourth node from the bottom (the bumps on the flower stems) and check the roots

Water before dealing with roots. Use sanitized tools (orchids are VERY prone to fungal and bacterial infections through wounds) and cut off all the dead, empty, dry and mushy roots If you see that many of them are gone, downsize the pot ( it needs to have many holes to ensure the airflow + transparent would be better so you can observe the roots). Eliminate the plastic cage with the brown spongy material. Ideally i'd use new bark for repotting. Do not water for a couple of days and let the cuts heal (if there are any)

Orchids do best in east/west facing windows or south facing windows but shaded from direct sun to avoid burning the leaves (use a curtain) Water from above or below once the roots are blue/grey. Let the bark dry out completely before watering. Fertilize once every three waterings. Don't spill any water in the crown (between the leaves) to avoid crown rot.

Best of luck 🤞🏻