what I want to do (主语从句)is(系动词) make a fresh start(不带to 的不定式短语作表语)
语言点:
当主语有实意动词do "做",表语用不定式陈述主语"做"的内容时,to 可以省略,也可以不省
再如:
The first thing for you to do is (to) find out where he lives.