I need to ssh into another machine using expect and a password and start a program there, then start a program on my local machine. How can I do this?

As said in the title, I am writing a script that should run on Computer A. Computer A should ssh on Computer B, run Program B, then exit the ssh session (Program B still running on Computer B) and then run Program A on Computer A.

I must use expect and I must use a password for ssh to accomplish this.

Here is my try so far (it is not working):

#!/bin/bash

#checks to see if programA is already running

if pidof -x "programA">/dev/null; then
    echo "Program A already running"
    exit 1
fi

spawn ssh username@{$1}
/usr/bin/expect "assword:"
send "password"
./programB & # run programB in the background
exit
./programA

Here is the script which is supposed to terminate the programs on both computers:

pkill programA
spawn ssh username@{$1}
/usr/bin/expect "assword:"
send "password"
pkill programB
exit

The script to start the programs doesn't work as expected. It starts both Program A and Program B on Computer A. It was also brought to my attention that I need to detach my ssh session because otherwise when I exit it on Computer B Program B will terminate.

Can someone provide me with the script which does what I want it to do, with explanations where I went wrong?

Thank you in advance.