My iPhone is not letting me set up

For service, see this Apple article:

If you see No Service or Searching on your iPhone or iPad

https://support.apple.com/en-us/HT201415

For Wi-Fi network connect to your Wi-Fi network, see the following Apple articles:

Connect to Wi-Fi on your iPhone, iPad, or iPod touch

https://support.apple.com/en-us/HT202639

If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network

https://support.apple.com/en-us/HT204051

my SIM card can’t be found or detected

See this Apple articles below:

Set up cellular service on iPhone

https://support.applehttps://support.apple.com/en-us/HT201328

How to unlock your iPhone for use with a different carrier

https://support.apple.com/en-us/HT201328