How do I write script in DS script window for drawing molecules.

Hello, everybody.

I am a new user. I've never been doing coding kind of script.

But I need, want to make some coding in DS.

Here, if I want make mathylation beta CD(cyclo dextrin), and I have alreald had b-CD perfect form. There are 21 OH-s position within b-CD, so, I would put methyl all of them(21). But I don't need all of them.

I need just to synthesize 4 methyl to OH-s randomly. Probably I would get some 21C4 methylated-b-CD-s.

How could I make the script the algorithm? I don't want to draw all of them..

Please help me and let me know.

Thank you.

Sincerely AHRI