Brick store ventilation and moisture control

[Saxsoulbrother]

I have a brick garden store, approx 4’ x 10’ that is very damp; I had the roof replaced a while ago, so it’s penetrating rather than leaking. There is currently no ventilation. I’m thinking I probably need to install air bricks at either end to get a through flow of air, but have read conflicting advice on the height to install those - any thoughts? Also, should I be considering some kind of coating for the (brick) floor and/or walls? Thanks in advance.