it is hard to understand what you mean.
You can't for instance have the terminal wait for a user to click its window.
(But you can poll for a keystroke after the terminal window is opened.)
You'd have to use a dialog before your code, in order to make the user enter the terminal consciously.
display dialog "Press ok to enter the terminal" buttons {"Cancel","Enter"} cancel button 1 default button 2
Other than that, the way you'd need to use system events to send keystroke to the Terminal
tell application "System Events"
tell application process "Terminal"
keystroke "abcd"
end tell
end tell
You can poll for a keypress in the do script command to your terminal with this:
read -n 1 -s MYCHAR </dev/tty
This will force the user to press enter from a do script
a=`read`