Great job!  The conditionals are correct!

(review at https://www.ef.com/english-resources/english-grammar/conditional/)

I'll be happy,if you would correct my sentences about conditionals.  ("would" for politeness)

If we met on/next Sunday, I would give you /back your book/your book back/.  (both forms OK)

If we had met last Sunday, I would have given you /back your book/your book back/.  (both forms OK)

If you had given/loaned me your book, I could have given you it back on Sunday. (pronoun required)

Or: If we had met on Sunday, you could have given/loaned me your book.

Thanks for your time!

Notes - 

I'll - I will

I'll is the casual spoken form (also used for casual email)

I will is the written form 

would/could - polite requests

I'll be happy if you would correct 

as a conditional - "I will be happy, if you correct" is a correct form

as a polite request, "would" and "could" are used to soften the request

examples:

My car won't start.  Take me to work.  (brusque command)

My car won't start.  Will you take me to work?  (brusque request)

My car won't start.  Would you take me to work?  (casual request to a friend or family member - no obstacle is expected)

My car won't start.  I would/will be very grateful, if you would take me to work, please.  (extra polite request)

My car won't start.  Could you please take me to work?  (casual request to a friend or family member - an obstacle is possible)

to give -

(a) to give as a gift

(b) to loan temporarily

to give back - 

(a) I will give you your book/it back.

(b) I will give you back your book/it.

(c) I will give your book/it back to you.

(d) I will give back your book/it to you.

As a note, English usually avoids modifiers between the verb and the object(s), so "give (your book) back" is preferred over "give back (your book)."  

Phrasal verbs are tricky.  Here's more information.

https://www.fluentu.com/blog/english/english-phrasal-verbs/

I'll be happy,if you correct my sentences about conditionals.

If we met on Sunday, I would have given you your book back.

Alternative way, often you will come across these alternate phrasings by different people where word order is reversed.

{you can't have given the book back in the past} via using the word WOULD

If you had given me your book Earlier. I could have given it back to you on Sunday.

{rephrased it is longer but a bit more natural}

{same problem again you needed to have had the book earlier than Sunday, to give it back}

Or: If we had met on Sunday, you could have given me your book. OK fine
Thanks for your time!