In this sentence:
Será mejor que aparques lejos del centro.
(It'd be better if you park far from the town centre.)
We are using the future tense in Spanish but it is not referring to a future event. It is a way to make a suggestion. "Será mejor que..." is used to suggest something to someone.
In English this suggestion doesn't work with the future tense, you need to use the conditional instead to convey the same as in Spanish. "It'd be better if..."
Sometimes translations are not literal. We try to use the most natural translation in English all the time.
I hope this helps