It's best to avoid table salt which can contain anti-caking agents that are harmful to fish. Lake malawi salt contains more than just sodium chloride, so I wouldn't use that for treatment either. I know API makes aquarium salt, which you can pick up at any LFS, petco, petsmart, etc.
Starting at 0% salt in your aquarium water, you add 1tsp salt/gallon which increases the salt to 0.1%. After 12 hours, add another 1tsp/gallon which will increase the salt to 0.2%. Then again after 12 hours, add 1tsp/gallon which will increase the salt to 0.3%.
If at any point you notice signs of stress, immediately do a 50% water change (this will cut your salt concentration in half). Use the largest salt concentration up to 0.3% that your fish tolerate well.
If the percentages still don't make sense, just ignore them and follow the directions