how to string commands shell using & code example

Example 1: ubuntu run multiple commands in one line and let them run after close shell

# Sequential
(myCommand1; myCommand2) &
# or
(myCommand1 &) && (myCommand2 &)

# Parallel
myCommand1 & myCommand2 &

Example 2: two bash coomand in same line

# cmd1 && cmd2
$ cd myfolder && ls  # run ls only after cd to myfolder

# cmd1; cmd2
$ cd myfolder; ls   # no matter cd to myfolder successfully, run ls

# cmd1 || cmd2
$ cd myfolder || ls  # if failed cd to myfolder, `ls` will run