Unfortuantely, your tank won't have cycled yet so the ammonia levels with that many fish will be very toxic - I'm guessing almost deadly levels. Cycling a tank can take anywhere up to 8 weeks as it will go through the nitrogen cycle.
First stage is ammonia and this is why test kits are so important. You would need to test your water daily until your tank is fully cycled. The reason is so that you can monitor how high these levels get and do massive water changes to bring the levels down.
Second stage is nitrites - almost as deadly as ammonia and also need to be monitored daily.
Final stage is nitrates which is the total conversion of ammonia and nitrites.
When you ask how will they live with 60% of the water gone, you will be replacing it with fresh, dechlorinated water so they don't have to be in 40% for long.
You're in a tough situation because of 4 main reasons:
1) you have way too many fish in a 10 gallon - which will make your water very toxic quickly
2) your tank hasn't cycled yet so it's important to do daily waterchanges - sometimes twice a day
3) you unfortunately don't have test kits which will indicate to you how often and how much water needs to be changed - keeping their environment as healthy as possible
4) they have ich which if it's to be successfully treated, must be done so in perfect water
So all in all, i can only suggest (if you are unable to buy test kits) large daily waterchanges that will need to be measured to replace the correct amount of salt.
It may be a good idea to write down your salt levels ie. 0.1%, 0.2% or 0.3% which equates to 1, 2 or 3 teaspoons of salt per gallon and make sure that whenever you are in salting your tank, you replace the correct amount based on the amount of gallons you change.
I hope this all makes sense and I wish it could be simpler but hopefully with some diligence in waterchanges and salting - they should do ok for now