The clear implication is that £350m per week is available, and that it will be spent on the NHS.
£350m is the gross figure, it ignores the > £200m per week we get back.
There is not going to be any increase in NHS funding. Anyone who voted leave because they thought there would be an increase in NHS funding hasn't been paying attention - the NHS has seen deep cuts in recent years and those are only going to get worse after Brexit.