Install iStore App Store
iStore website: https://istore.linkease.com/repo/all/store/
Download the 4 files circled in red (see the image below)
A total of 4 files.
Log in to the OpenWRT management page: Go to System ---- File Transfer
Upload the software packages, and install these 4 ipk files separately.
After installation, refresh the OpenWRT management page, and you will see the iStore store!