Iron Spikes come in bundles of ten. As a Utilize action, you can use a blunt object, such as a Light Hammer, to hammer a spike into wood, earth, or a similar material. You can do so to jam a door shut or to then tie a Rope or Chain to the Spike.
RollQuest ships the D&D 2024 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.