Even after putting a new sim slot phone network is not available

First of all, check that your phone supports the kind of SIM you are using (which will probably not be the case). Then make sure that there are no problems on your network provider company's side. Try updating (if there are any available) and restarting the phone a couple of times, as well as clearing the partition cache of the system. If you have replaced the SIM slot and the problem still persists, having also checked and done the above, the problem will likely persist. As a last resort, try to enable the SIM, if it is recognized, by following these steps: Go to settings, then "Network and Internet", then "SIM card and mobile network", then "SIM card Information and Settings" menu, select the desired SIM card, then slide the "Activate SIM card" to the enabled it, and done!

Hope this helps!