How to build a custom importer which can import/export MPP file with multiple hierarchies using Forge atlassian in cloud jira?

How to build a custom importer which can import/export MPP file with multiple hierarchies using Forge atlassian in cloud jira?
Also, need to setup a custom UI which can import the mpp file and then validates and creates issues in jira. This mpp has got multiple hierarchies and they need to be linked as parent-child linkage.