It appears to be as stated a couple posts up. И is used as and for related objects where А is used for things that are unrelated. Like how В is used for both in and on.
Though both may seem usable in that sense, I believe но is also one that sees use. Whether theyre necessary or not seems up for debate. Russian seems pretty laid back with how it operates.
Noun cases are especially nice. I love how prefixes and suffixes are a shortcut to understanding. -ого indicates a place. -ая and others also seem to ease the learning process.
It has a lot of culture references though. You cant learn russian without learning her history.
Like how красна (красный?) is red, and red can be used in many ways. The word for beautiful itself is a modification from the root "red". So like Chinese, Russian seems to be a language with extremely logical building blocks, much like Chinese.
Only with a far less complicated writing method that looks pretty gorgeous in its own right.
(Cyrillic cursive can burn, though.)
"and" in English can actually mean a lot of things, so it's only natural that it doesn't always have the exact counterpart in other languages. When you use it to connect things together (as in my brother and my sister), you can always translate it as "и". When you use it to compare things (when you can sort of replace it with "but") - use "а": мой брат глупый, а моя сестра умная (my brother is stupid and my sister is smart) When you use it for an inquiry, it's "а" again: а моя сестра? (and my sister?) When you use it to connect sentences, it gets complicated, but you can kind of use both
"a" is used when expressing differences between two things (i.e. how they used "a" in the sentence "Это радио, а не мотор". "и" is the more simple conjunction like how it is used in this sentence)
I'm not for certain myself but this is what was said about "and" in a previous discussion.
Мои [muh-EE] брат и сестра, мои мама и папа, etc.
"Мои" = plural. In Russian plural forms of pronouns usually have no masculine / feminine differences, so "my sisters", "my brothers" and "my brother and sister" = МОИ сёстры / братья / брат и сестра.
P.S. The same situation with adjectives: высокий брат, высокая сестра, высокие братья, высокие сёстры, высокие брат и сестра (высокий [vy-SO-kiy] = tall).
There should be a button at the top left near 'Tips and Notes'. It looks like a sideways switch, and it can turn the Russian to either Cyrillic or Roman. Hope this helps!