well in brief
there are 2 account
current account
capital account
current acount has 2 types
visible trade: has imports and export that are visible
invisible trade : imports and export at are 'invisble' in terms of gaining or losing foreign currency
capital account
this consists of changes in external assets and liabilities
well usually this is all added up in balance of payment....imports and negative and exports are positive
overall positive is surplus
overall negative is deficit