Your Chinese is great :)
I give you 3 most popular usage
sometimes,
得(or 不得不) = have to
eg:
"I have to go" can be translated to “我不得不走(了)”or“我得走(了)”. Both are correct.
sometimes,
得 = must = 必须
"I must go now" = "我(现在)必须走(了)" = "我得走了"
sometimes,
得 = can
means permission.
but generally, we use "不得" = "cannot"
eg:
不得入内 means "forbidden"
word for word translate: cannot enter inside (of a building or an area)
and, Xuen's answer, the 3rd,
3.Used between a verb and it's complement to indicate possibility.
拿得动(can carry sth);办得到(can do sth);回得来(can come back)
is also popular but usually in oral language.
拿得动=可以拿动=能拿动
办得到=可以办到=能办到
回得来=可以回来=能回来
as i said, 得 = can
hope it can help you :)