this one has been done several times in the past. The contract that you're thinking of is the letter of engagement.
The downside to this is that it's one of the few documents that bookkeepers don't tend to share as in most cases we're not legally trained so it's possible that the engagement letters would not stand up in a court of law and the last thing that one wants is to be put in a position where a letter that you created causes someone elses headaches!
But whilst we're not likely to share the engagement letters we are a freindly bunch on here so a few pointers to get you started.
Whilst there are plenty of useful posts on this subject that you will find on the site, have a read of this one that is quite recent and may help you more than most in that it gives you a framework to work to :
Hope that helps, welcome to the forum and good luck with the new venture,
kind regards,
Shaun.
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Shaun
Responses are not meant as a substitute for professional advice. Answers are intended as outline only the advice of a qualified professional with access to all relevant information should be sought before acting on any response given.