WordPress Site Merge and Template Installation

I need help migrating posts and images from my new WordPress site to my old site. Additionally, I need assistance with the initial installation of a new WordPress template that I have already purchased.

Requirements:
- Migrate all posts and images from the new site to the old site.
- Ensure a seamless migration with no issues.
- Install the purchased WordPress template correctly on the old site.

Ideal Skills and Experience:
- Proficient in WordPress content management and migration
- Experienced in WordPress theme installation
- Detail-oriented to ensure everything is functional post-move.