for each character: (use $mid to get it)
- get it's ascii value -> $asc
- convert it to binary -> $base(xx,10,2)
- make sure it's 8 digits long (put 0's in front of it, or add 256 to the $asc value before and then take only last 8 digits ($left or $right)
- append it to output string
msg the output

That's about it, but be careful because each character will take up 8 characters after conversion, so you can only write very short lines (25 characters) before it gets chopped off

To decode it:
chop binary stuff in 8 character chunks ($mid again)
use $chr($base(bbbbbbbb,2,10)) to get the ascii character and append it to output

you can search the help file for alle the $identifiers used for more info