To have any chance of being able to tell you which chain length to use, one would have to know your chainstay length.
There are chain length calculators for fixies etc. don’t know if there are any for derailer gear bikes.
Anyhow, measuring the frame close enough to calculate chain length takes more effort than fitting a chain to the bike.
And since chains are generally sold over-long, you have to buy a chain breaker anyhow.
So you might as well invest some time in doing a net search on ”chain length sizing” and learn to do it yourself.
Compared to the overall difficulty of building a bike, chain length sizing isn’t much to worry about.