Hi Oscaroscar
All you need to do is keep it clean and dry. Wash and dry it once or twice a day. A cotton bud (Q TIP) is good for this. Wet a cotton bud with clean warm water. Cive the cord stump a good wash with this. Make sure you get right down to the bottom of the stump. (don’t worry, it will not hurt your baby, in fact your baby has no feeling in the stump. When you have washed the stump it needs to be dried. You can do this with another cotton bud or two. It is also a good idea to dry the stump after a bath again using a cotton bud.
Keep an eye on the skin around the stump for redness as this could be a sign of infection. Some mild redness is quite normal however if the redness spreads for more than about 0.5 cm from the stump then it should be investigated.