"Yes, this is a sweater."
Translation:Да, это свитер.
They are different letters entirely! З is the Russian "Z" and is dimpled inward. Э is the letter "eh" and is more like a backwards "C" with a dash added in the middle. (It's located on the apostrophe/quotation marks key of an English keyboard! The Russian alphabet has more characters than ours so they take up some of our other keys)
Both of the Russian characters Э and Е ("yeh") would be represented by an English letter "E".
They can mean "this" except I believe ето is just a misspelling of это.
этот means "this" and it's used to define masculine nouns. For example этот свитер = this sweater (basically all nouns ending with a consonant are masculine)
это also means "this" but it is neuter form, so it's used word neuter nouns. For example это молоко = this milk. There are three linguistic genders in Russian. The third is feminine and it uses эта for "this __".
However, это is also another word that is used as a standalone word to refer to basically anything when you want to introduce it: Это моя мама. - This is my mum. Это свитер. - It is a sweater. Это рыбы. - They are fish (plural). So in this use, это basically translates to "This/It is..."
On a PC Ctrl Win key 'O' brings up an on-screen keyboard. To add/change a language go to Settings, time and language, language - and add your new language. Save this. You can then toggle between English and your new language on the screen by clicking the 'ENG' button on the right hand side of the taskbar next to the time.