Firstly, do you have a dumped Wii U otp.bin and seeprom.bin? (And your profile data*)
You need those to connect online to Pretendo services.
These dumps NEED to be from your real Wii U console. Using dumps online is usually unsafe and not recommended by mostly everyone.
If you do have those files, place them in the right directories. You can find out more in that ‘Online play tutorial’ button there.
also gonna ping @support-helper for Cemu help
@cemu_gamer Do you own a Wii U?
If you don’t then we cannot help you. Without your own Wii U to pull console files from, you cannot access Pretendo Network
Downloading online files from a console which is not yours is piracy and we will not assist with it.