'To download the OV-10A you must download the zip via the links in the #Annonce or #ov10a_bronco channel of the Split-Air Discord server. The Link direct you to a Gumroad website with a little description of the mod. You can choose if you want to financially support the Split-Air or not. The Bronco will stay a free mod, you are not forced to pay anything. After that the Gumroad request your mail address, but you don’t need any account. Finally you have access at the Zipped file of the OV-10A BRONCO.'
Here is a link that you get from the above, worth a try https://app.gumroad.com/d/70280cc299d3816d9dbcc446caab13c3 unless someone has another link.
You unzip the file then copy the mod OV-10A into the mods/aircraft folder in the saved game. The file path: C:\Users\NAME\Saved Games\DCS (.openbeta)\Mods\Aircraft\'The mod Unzipped'
Current version is v1.08