The main steps to attach a phone to a network

Hello dear,

Please find an overview related to your questions.

UE is Off
Power On UE
Frequency Search 
Timing Sync 
Cell Search: Normally a UE would find multiple cells in this process
Cell Selection 
MIB decoding
SIB deconding
Initial RACH Process 
Registration/Authentication/Attach
Default EPS Bearer Setup
Now UE is in IDLE Mode
If the current cell become weak or UE moves to another cell regisn) Cell Reselection
When Paging message comes or User make a call) RACH Process
Setup Dedicated EPS Bearer
Receive data
Transmit data
If UE power is percieved too weak by the network) Network send TPC command to increase UE Tx Power
If UE power is percieved too strong by the network) Network send TPC command to decrease UE Tx Power
If UE moves to another cell region) Network and UE perform Handover procedure
User stop call and UE gets into IDLE mode