What's the difference between THEN and THAN?

'Than' is the word you use when comparing -

I am older than you. Wine is stronger than beer

An elephant is bigger than a turkey, and so on.

'Than' nearly always comes immediately after a comparative adjective.

What is a comparative adjective?

Adjectives are words that describe or qualify nouns -

red car, sweet wine, old house

But most adjectives come in three flavours, positive, comparative, superlative -

big, bigger, biggest or good, better, best

The comparative is the middle one, and ends in -er

So, be looking out for those -er adjectives, and always use than straight after.

What about 'then' ?

'Then' is used when talking about time -

Do this first, then do that. or, I turned left, then right.

Then is also used with If -

If you are thirsty, then you should drink water. (You can often miss out then altogether, but you can't use than in its place).

Now, just to finish

There is one common but wrong use of than.

You should not say different than. The correct way is different from.