えき が  あって、べんり  です
There's a station,
​and it's convenient
Simple sentences can be combined into one compound sentence by changing the verb form at the end of the first sentence to the て-form. ​
BEGIN WITH TWO SIMPLE SENTENCES:
ゆうびんきょく は、おてら の　前に　ある。
ゆうびんきょく は、えき に　ちかい　です。
  • ​​The post office is in front of the temple.
  • The post office is near the station.
COMBINE THE TWO SENTENCES INTO ONE COMPOUND SENTENCE BY CHANGING THE JOINING VERB ENDING TO THE  て FORM:
ゆうびんきょく は、おてら の　前に　あって、えき に　ちかい　です。
  • ​​The post office is in front of the temple, and near the station.​
ANOTHER EXAMPLE:
私 の　まち は、うみ の　そば に　ある。
かんこうきゃく は、たくさん　くる。
  • ​​My town is near the sea.
  • Many tourists come.
私 の　まち は、うみ の　そば に　あって、かんこうきゃく は、たくさん　くる。
  • ​​My town is near the sea, and many tourists come.
Using a variety of sentence types and lengths makes our language (written or spoken) more interesting, and therefore more engaging for our audience (reader or listener).
In these videos, Patrick from Kanji-Link explains how to conjugate the TE form, and how to use the TE form to link sentences. 
A heads up: Patrick refers to ICHI-DAN verbs as 'Type 2 verbs', and GO-DAN verbs as 'Type 1 verbs'. This is a different classification that some teachers outside of Japan use. Confusing!