Hey, welcome.
Right a much easier way of doing a responce is to to use 'enter next command into a string' script, this means that the next thing the player types doesn't run like normal but instead is stored as a string, you can then do an IF (conditional) to see if it's equal to say 'yes' OR 'yay' OR 'yeh' (etc) THEN run the the scripts you want if they said yes, in the else put the 'no' answer stuff. Just repeat that process for whenever you want the player to reply, and keep going.
If you want to do it differently, put the specific yes/no 'if' stuff into a procedure (tools/procudures), have 'enter into script' , and then the IF, the 'yes' responce should turn flag 'yes' on. and 'no' should nothing. This is the clever bit, just above where you have the 'enter into string' script (you can re-order the lines using the up and down arrows at the top), put a 'turn flag 'yes' off'.
In the speak section of the person (which is where I'm assuming you're running the conversation from), have them say their thing, and when you want a responce, run the procedure (run script/run procedure), after have an IF seeing if the flag is on... THEN will be what they say to 'yes', ELSE to 'no'.
Expanding upon this:
You could put a number before different responses which are more than just 'yes' or 'no', then IF to see which number they typed, so what they said.
Another way of doing talking:
Have an 'ask (person) about (topic)' command. This is a little tricker to do though, and can be done a few ways. First way is it runs a procedure, which firstly turns a flag off, then has several IF's after each other (not inside eeach other) to see what 'topic' it is, then it can IF's to see what people say to that or the 'default' reply is (if they don't use one of the others). There is a slightly different way of doing that bit but with properties (which i'm using in my game).
In each topic script (the bit for responses), you also put a line in to turn the flag on. After all that topic stuff, you have one final IF to see if the flag is still off (topic not valid), and say 'I don't know what you're talking about' kind of response.
Hope you understand this and it was helpful, if not just ask and I'll try to help some more.