Cost basis versus expenses on short term flip

[Sue Gyure]

I purchased a property in Jan 2019 and sold it in May 2019. I had not intent of selling it but the renter wanted to purchase it.  

This is my first rental property and I am working on my taxes. Due to the fact this will be a short term gain, is it better to put whatever expenses I can into the cost basis, so my capital gains is less or do the expenses seperately?

Thank you for your expertise!

Sue