A character inserter plugin, but with my own character type which is still extremely similar to R6

Hello, guys and gals and others! I’ve got a question for you, as an Animator. It’s got to do with a plugin I’d like to create for myself and a group of others. I should probably clarify that I have no experience in scripting in any scripting language.

I created a model a year ago that since has been updated. (It’s a model that looks like R6 but has an invisible animatable lower and upper torso.)

What im trying to achieve:
Open up a menu with this plugin, and be able to insert this model, but be able to insert custom ID’s for the shirt, pants, everything.

I’ve looked at some code, and honestly, I haven’t come far. I did get a rough image of the UI, but truth be told I am in no way an expert at this. I did get the plugin button, though!
I’m sorry if this is quite the big favour to ask. But let me summarize with some examples:

I’d like to create a character inserter (Like the famous plugin that some people may know), but with my own character type (R7). How do I go on about this? Thanks!