The Romans, Arabs, Spanish, French and British all tried to claim Malta in history because of its strategic position.
--------My question is whether the part 'Spanish, French and British' are properly used, because I have learned words like Spaniards and Britons and think they should replace Spanish and British. Am I right?
'Spaniard' and 'Briton' are individuals; So here 'The Spanish, the British...' are right.
'The Spanish sent the Armada to invade Britain.'
'When Sir Francis Drake was told that the Spaniards were coming, he...' [is said by some, in a story that doesn't entirely convince me, to have] '...finished his game of bowls.'
You could also use 'Spanish' in the second sentence, but as '-ard' endings tend to be pejorative (like 'coward', 'bastard' and other less current words like 'dullard' and 'Lollard') I think the '-ard' version captures the spirit of the (Elizabethan) times better.