Real implementation of Diffie-Hellman [on hold]

I’m making a cybersecurity project where I need to implement a symmetric key exchange between two parties. Although I understand how Diffie-Hellman works in theory, how can I actually implement it(or use an existing implementation of it) for a project? So far, I have used OpenSSL to generate RSA keys(for signatures), but am stuck on getting some sort of DH implementation.