Please help me with my sentences

Could someone please help me by explaining what the grammatical errors are in these sentences? Can you explain in detail grammatically why the sentences are wrong?

There are unnatural word choices and unnatural positioning of certain words. These are likely due to interference from your own first language.

I would let you as soon as possible.

A fuller context would help. If you changed 'would' to 'will' it would be alright. Also, the verb/preposition after 'you' is missing [know/have it/in/out/see. That wouldn't matter if the context was known to the parties involved.

We put there our luggage.

This is possible in English but it isn't a natural word order. Locative 'there' is usually at the end.

On five o'clock I want to eat my tea.

'eat' isn't used for liquids, 'drink' is the verb used.
'on' sounds strange to me, 'at' is the choice for my dialect of English but I can't say for certain whether 'on' is impossible for all English dialects.

Thank you for the informations.

'information' is an uncountable noun, no 's'.

We have got three children. There are six, eight and eleven years old.