How to use parameters in batch files

Sample1:
Fomat. bat
@ Echo off
If "% 1" = "A" format:
: Format
@ Format:
@ Echo Please insert another disk to driver A, then press any key.
@ Pause
@ Goto fomat
This example is used to consecutively format several floppy disks. Therefore, you need to input fomat. bat a in the DOS window ~ Pai_^
Sample2:
When we want to establish an IPC $ connection location, we always need to input a large number of commands. If this is not the case, we will make an error. Therefore, we should write some fixed commands into a batch, assign the IP Username Password in front of the parameter to this batch for processing, so that you do not need to execute commands every time.
@ Echo off
@ Net use \ 1% \ IPC $ "2%"/u: "3%" NOTE: Here password is the second parameter.
@ If errorlevel 1 echo connection failed
How can we use parameters?