While you wear these boots, your walking speed becomes 30 feet, unless your walking speed is higher, and your speed isn’t reduced if you are encumbered or wearing heavy armor. In addition, you can jump three times the normal distance, though you can’t jump farther than your remaining movement would allow.
RollQuest ships the D&D 2014 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.