Generate CSR for SSL in oracle Cloud integration platform OIC, OCl, to connect to external web service — 2

I have oracle Cloud integration platform to build integration I want to build integration that connect external web service to consume thier Data thier requirments to call thier API using digital signature with Sha256 Rsa to call thier API Restful,
I have to generate CSR certificate signing Request with thier info then they will issue and sign ssl certificate in response to my CSR
Then I have to import certificate in response to CSR Along with complete certificate chain
So, I need some one expert in Oracle Cloud
That alredy implement same senario
I didnt know how to generate CSR and other stpes.
I want some one Already implementd this Senario in oracle Cloud Infrastructure OCI, and oracle integration cloud