Meaning of doing

Hello trainers,
please tell me When should i use preposition [to] or [for] with the word suited?
e.g. 1- He was not suited for /to this throne. 2- He is not suited to/ for you. please explain the difference between both of them.my next question is;
kindly tell me the meaning of doing words in the following heading given below;
' Here are few sentences .Underline the doing words in them.' my next question is ; Is it impossible to build the following sentences by using' so.. that'? we can build the sentences with the conjunction 'so' but not with 'so..that' Is it true? if so please explain me.
1- As it was raining, i stayed at home.[ It was raining so i stayed at home]
2- I have already seen the film, i can't come.

Thanks in advance