You'll need to post a bit more information than that if you want assistance from the Community Forum.
Did you successfully activate the SIM?
Is your phone unlocked for use on any network?
When you install the SIM in your phone what happens?
Any error messages?
Do you have a connection to the 48 network - i.e. signal bars?
If not then if you do a manual search for networks can you see and connect to 48?
If you do have a connection to the network then does anything work?
Incoming/outgoing calls, incoming/outgoing texts, mobile data?
Did you configure your APN settings for mobile data to work?
If you're on Android then you can text "APN" to 50048 and follow the instructions here to configure your settings:
If you need to contact 48 support about this then see the links in my signature below.
