VKO GOST R 34.10-2001 (described in RFC4357), Key Agreement Algorithm. Looking for its implementation/detailed description/examples
You can start by reading:
https://github.com/openssl/openssl/blob/OpenSSL_1_0_2-stable/engines/ccgost/README.gost
It has examples on how to generate GOST certificates.

After that I would suggest running a test SSL/TLS connection with those certificates and openssl s_client and openssl s_server utilities. If it works, you may then recompile OpenSSL and make it dump all needed intermediate data during SSL handshake to stdout. You can then have as many reference examples as needed.

Also, have a look at
https://github.com/openssl/openssl/blob/c64879d3f3cc4c7f1c436a9fe3bd109847a23629/test/gost2814789test.c
to have an idea on how to call GOST algorithms from OpenSSL.