Transfer photos from my PC to my ipad mini. I have tried iTunes but I don't understand it

Try downloading an app called Shareit.
When attached to the same WiFi, you can transfer Photos directly from iPad to iPad and even between Windows and Andriod devices. You start Shareit on both devices and send from one and receive on the other.

With iTunes you can check this guide:
Step 1: Open iTunes on your PC and then connect your iPad to computer. When your iPad info has been recognized by iTunes, you need to click on "File > Add File to Library".
Add File to Library
Step 2: When the videos have been saved to iTunes, you can continue to solve how to transfer files from PC to iPad by clicking on "iPad icon > Settings > Movies > Sync Movies". Then you need to choose the videos you want to transfer to your iPad from computer and click on "Apply" to confirm your changes. The sync process will begin and you need to wait until it is over. Eventually, the computer videos will be available on your iPad.
Sync Movies
If you want to transfer PC files to iPad, not videos, but photos, songs or other files, you can also refer to the steps above. You just need to add the files you need to transfer to iTunes library and then click on the corresponding tab to sync to your iPad. This is not hard to handle to copy files from PC to iPad at all.

if it still failed, you can try other ways, check
https://www.leawo.org/tutorial/how-to-transfer-files-from-pc-to-ipad-with-and-without-itunes-1361.html

Maybe you can use iOS Assistant tool to help you transfer photos from pc to iPad mini. You just need to connect iPad mini to computer via usb cable, start the iOS Assistant tool. A short time scanning later, you can easily transfer photos to it. Coolmuster iOS Assistant Freely Manage iPhone iPad iPod

Www.imobie.com/support/how-do-i-transfer-photos-to-my-iphone.htm Yes, you can use iTunes to transfer photos from PC to iPad, but iTunes is a little bit complicated.

1. Create a folder containing images you want to transfer to the iPad
2. Connect the iPad to the computer, launch iTunes, and select the iPad from the devices list
3. Click on the "Photos" tab
4. Check the box next to "Sync Photos from" and select "Choose folder..."
5. Locate and select the folder you created earlier containing the pictures you wish to transfer over, click on "Choose"
6. Click on "Apply" to begin syncing the photos from the computer to iPad