Executing commands sequentially

Hello.
I am new in shell script. Could anyone help me?
I have un shell script. I need each command in it be sequentielly, when the first command ends the second starts. When the second ends et third starts, and so on
Thanks in adavance

What you are requesting is the default behavior for most commands in most shells.

What shell are you using?

What operating system are you using?

What commands are you trying to run in your shell script?