You will need:
3 wood planks
3 wool of any color
1 flower of any color
-Craft the bed in the bed section of the first tab in the crafting table menu
-Turn the flower into dye in the decorations tab of the crafting menu
-Hit
to go the dye section. Then
to switch to the second tab
-Find the find the dye you chose then hit
-Exit the menu and place down the bed