Both computers are on the same network.
Something easy please that let's me choose the files to transfer.
I thought I posted this but can not find it now.
Does your new computer have an easy transfer app?
USB memory stick or external hard drive and swap between each computer.
Use a remote desktop app like Anydesk on each computer.
External hard drive is easiest. Resilio Sync is also fairly easy to ste up and transfers across your LAN, wired or wireless, but most networks are a lot slower than even USB2.
Just share the folder (under File explorer right click, properties, sharing) then use File Explore on the other computer to go to that PC and copy paste.
Depending on what the user has said about the network when first connected, and what windows think the network is public or private windows firewall can easily block this, and if you do not know how to fix this, this can be hard for a novice person to get going, easy after firewall sorted tho.