「に」と「で」 にis used with a static verb and で is used with a active verb. テーブルの上<うえ>にボールペンがあります。There is a ball-point pen on the table. 銀座に鈴木さんがいます。There is Mr./Ms. Suzuki in Ginza. 妹<いもうと>はテーブルの上で絵<え>を描<か>いています。My younger sister is drawing a picture on the table. 鈴木さんは銀座でてんぷらをたべます。Mr./Ms. Suzuki will eat tempura in Ginza. 鈴木さんは東京に住んでいます。Mr./Ms. Suzuki lives in Tokyo.＝Mr./Ms. Suzuki has his/her house in Tokyo. 鈴木さんは東京で暮<く>らして／生活<せいかつ>しています。Mr./Ms. Suzuki lives in Tokyo.＝Mr./Ms. Suzuki works and spends his/her time in Tokyo. 鈴木さんは東京銀行<とうきょうぎんこう>に勤<つと>めています。Mr./Ms. Suzuki works for Bank of Tokyo.＝Mr./Ms. Suzuki has a job at Bank of Tokyo.＝Mr./Ms. Suzuki belongs to Bank of Tokyo. 鈴木さんは東京銀行で働<はたら>いています。Mr./Ms. Suzuki works in Bank of Tokyo.＝Mr./Ms. Suzuki plays an active part in Bank of Tokyo. 「に」と「へ」 にis a destination / arrival point (＝in/on/at) and へ is a direction(＝towards). 日本<にほん>に行<い>く。to go to Japan 日本へ行く。to go to/towards Japan 日本に着<つ>く。to arrive in/at Japan 日本へ着く。INCORRECT

This answer is just MY opinion, so I hope someone also answer this. When we say "で", the focus is the methods (like HOW you do). When we say "に", the focus is the destinations (like WHERE you go). EX) 私は電車で公園に行きます。 　　　I go to the park by the train. "に" and "へ" are even harder to differentiate lol When we say "に", the focus is the destinations (like kind of focus on that). When we say "へ", the focus is the destinations (like REALLY focus on that). We say "に" for also time. EX) 私は午後2時に公園へ行きます。 　　　I go to the park at 2pm. (We don't say "私は午後2時に公園に行きます". It sounds awkward.) I hope it helps :)