Company K 302nd from NY in 1918

"302nd" refers not to a division but to a regiment or possibly (but less likely) a battalion.  There was no 302nd division in the US Army during World War 1. Unfortunately there were several regiments with the number "302nd".  You would need to find out what type of regiment (infantry, artillery, etc.).

Given that you specify that he was from New York, he might have served in 302nd Engineers, given that they were part of the 77th Division that drew mostly on men from New York.  However that was by no means the only possibility for a regiment that he might have served with. 

I suggest you request his military records to see what additional information they can provide. See here for instructions about how to request your uncle's Official Military Personnel File: https://www.archives.gov/st-louis/military-personnel-archival

Also, if you have any pictures of him in uniform, or even part of the uniform itself, there may be additional clues such as unit patches and regimental collar insignia.

If you can figure you which unit he was in, you can then search for a book, article, website, or other secondary source with information about the unit. You can also request the records of the unit from the National Archives at College Park.

See below for some examples of the online resources that may be useful in researching World War 1.

https://history.army.mil/html/bookshelves/resmat/wwi/prologue/default/index.html
https://history.army.mil/html/bookshelves/resmat/WWI.html

https://www.archives.gov/topics/wwi

https://www.archives.gov/research/genealogy/wwi

https://www.familysearch.org/wiki/en/United_States_World_War_I_Service_Records

Dear Ms. Bringas-Garcia,

Thank you for posting your request on History Hub!

We searched the New York Military Museum & Veteran Research Center but were unable to determine what kind of unit you are seeking. If perhaps, the 302nd was an engineer unit, then we located a history of the 302nd Engineers that was part of the 77th Division. The 77th was organized during WWI with volunteers from New York and New England.

We searched the National Archives Catalog and located a series titled Records of Divisions, 1917 - 1920 in the Records of the American Expeditionary Forces (World War I)(Record Group 120) that includes 31 boxes of records pertaining to the 77th Division. For access to these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at archives2reference@nara.gov.

We hope this information is helpful. Best of luck with your family research!