add swich to stack (cisco 3750)

I want to add 2 switches to my stack of 2.

Switch 1 is the top switch in rack and has a priority of 15

Switch WS-C3750X-24P-S   2 the is second switch in rack and has priority of 14

How can I configure the stack (provision configuration) so that the 3rd switch  in rack will get switch number 3 and the 4th switch in rack gets number 4

All swiches are exact same module

    Just do one-by-one method with following configuration only from the stack master.

Switch(config)# switch 3 provision switch_PID - put your 3rd switch into stack.

Verify the status of the provisioned switch. For stack-member-number, enter the same number as in Step 1.

Switch(config)# switch 4 provision switch_PID - put your 4th switch into stack.

Verify and save the config.

Note - switch_PID:

For type, enter the model number of a supported switch that is listed in the command-line help strings.

change the stack member number by using the switch <current-stack-member-number>  renumber <new-stack-member-number> global configuration command,

show swithc will show the current swithc number and priority

  3750-Stk>show switch

                                                   Current

    Switch#  Role      Mac Address     Priority     State

    --------------------------------------------------------

     1       Slave     0016.4748.dc80     1         Ready

    *2       Master    0016.9d59.db00     5         Ready

the new number goes into effect after that stack member resets (or after you use the reload slot stack-member-number privileged EXEC command) and only if that number is not already assigned to any other members in the stack.

A higher priority value for a stack member increases its likelihood to be elected stack master and to retain its stack member number. The priority value can be 1 to 15. The default priority value is 1. You can display the stack member priority value with the show switch user EXEC mode command.

    3750-Stk>show switch

                                                   Current

    Switch#  Role      Mac Address     Priority     State

    --------------------------------------------------------

     1       Slave     0016.4748.dc80     1         Ready

    *2       Master    0016.9d59.db00     5         Ready

Cisco recommends that you assign the highest priority value to the switch that you prefer to be the stack master. This ensures that the switch is re-elected as stack master if a re-election occurs.

How do you change the priority value?

    From the global configuration mode, issue the command switch stack-member-number priority new-priority-value .

    From the bootloader switch: prompt, issue the command set SWITCH_PRIORITY new-priority-value .

Even though the priority value applies immediately to the member, it will not affect the status of the current stack master. New priority value will play a role in the next stack-master election.

Yes the switches will retain their numbers even if you set different priorities.

The priority sets which switch in the stack becomes the master.  The number is just that - the number of the switch WS-C3750X-24P-L    in the stack.  Once it's set the number won't change unless you change it in the config.