Chinese Grammar Info provides an excellent write up on the three distinct de particles. See the site for the full article.
The main points are:
(的) de as the possessor or causing the possessive function:
wǒ de shū
Zhè shì nǐ de shū.
This is your book.
(地) de/di as the ly suffix
Tā hěn kuài de chīfàn.
He eats quickly.
(得) de as a potential complement
zuò de dào
Wǒ zhǐyǒu dài yǎnjìng dehuà cái kàn de qīngchu.
I can only see clearly if I wear my glasses.
UPDATES (per request in comments):
More on 得. The article further states that this version of de relates to two types of complements: potential complements (which indicate that the attached verb has potential to have the action happen) and degree complements (speaks to the degree/amount that a potential verb may happen).
tīng de dǒng
can understand (from listening)
tīng bu dǒng
can’t understand (from listening)
Note the basic structure where the verb is followed by a description that includes the degree complements; very well, badly, very tall.
[verb] 得 [description]
(a few more samples)
Nǐ shuō de fēicháng hǎo.
You said it very well.
Tā zuò dé bu hǎo.
He did it badly.
Tā zhǎng de hěn gāo.
She has grown very tall.
Beyond it's use as a particle, the article states:
得 as dé When 得 is pronounced dé in second tone, it’s a verb meaning
“to get” or “to acquire”.
得 as děi When 得 is pronounced děi in third tone, it’s a modal verb
meaning “must” or “have to”.