Hello.... I Want To Ask...what Must You Do,drink Or Eat In Oder To Get Fatter?

You want to load up on calories; namely carbohydrates, but moderate fat and protein as well.  For those with high metabolism, gaining weight can be as difficult as it is for some to lose it.

Some people's metabolism simply won't allow for much weight gain at all.

Food, McDonalds any places like that (including desert) and drinks, soda

I won't even ask why you want to get fatter but I would say that, eating McDonald's and never moving a muscle is a good start. Don't do it though, not healthy!

I eat lots of sweet and starchy foods and sugary drinks. That works for me.