Help for ligatures

I’m trying to create a font handwriting. For some letters I would like to create ligatures, for example “ss” or “tt” I tried to follow the tutorials but I can not. I create a new glyph with tt but if I try to change the letters the original t changes too, while I would like to insert a combination of two “t” combined with each other different from the original one. I hope I was clear. If you can explain to me how you would do with a child, thank you!

  1. Create a glyph called t_t (the underscore is important).
  2. In the glyph, decompose components (Glyph > Decompose Components, Cmd-Shift-D).
  3. Now you have outlines, which you can edit and adjust.
  4. In File > Font Info > Features, click the buttons Update and Compile.

Thank you for the answers, i try but and now i’m able to change letters detail without change the original. but when I finish the steps you indicated to me and i type words with tt remain the same as before :frowning:

You have to activate the ligatures. It is described in this tutorial:

Ok thanks a lot! the last thing, if i want substitute some of last letter of word how can i do?

That is a little more difficult. There is a tutorial called Positional Alternates that describes steps.