These are things that cannot be customized. Let them know whats there in ur heart!
SOmething like - I am happy to be a part of this new work place and hope that this would be of mutual benefit.
Or I look forward to a great working experience!
Or just introduce urself and say how happy u r to be a part of the company.
I am not here to point out if wat was requested by u is roght or wrong. But, not everytime u wil have ppl to help u even with small things.
Please draft a letter by urself. Put in all what u would like to say. Save that letter on ur desktop.. have a cup of coffee... look back at it, and modify it. ! There u r!
None of us can help u with a better one than that.
I can say one thing.. make sure it communicates u r happy to be a part of the group and evenually look forward to working along with highly talented professionals.
Make them feel gud abt reading it. Thats it!
Pls dont write an essay tho..
Take Care!