You need the first "to" in "to make", but "to happen" should just be "happen." You need to use the base verb after modal verbs like "make" or "let", not the full infinitive with "to."

Modals and a few other verbs take a bare infinitive without "to": "May I dance?" "Let me speak" "Make it happen" "See him run" or "watch him run" "Hear her sing" or "listen to her sing" Other verbs need "to": "Permit me to dance" "Allow me to speak" "Do you want it to happen?" "Encourage him to run." "She hopes to sing" Unfortunately, you have no choice. You have to do it that way. There are only a handful of verbs that don't take "to", so it's not hard to remember them.

When you use “to + infinitive” with “make”, it has a different meaning. For example, if I say “I made cookies to give to the children”, it means “giving to the children” is the reason why I made the cookies.