How do I connect one django model to another in admin page

Change your admin.py code to this

from django.contrib import admin
from .models import *
# Register your models here.


class CommentInline(admin.TabularInline):
    model = Comment

class PostAdmin(admin.ModelAdmin):
    inlines = [
        CommentInline
    ]
admin.site.register(Posts, PostAdmin)
admin.site.register(Category)

This will show all the comments as a list inside each post's page in django's admin dashboard.