The conditional is one of the easiest Spanish tenses, as far as its formation goes. To the infinitive of the verb add the imperfect endings -ía, -ías, ía, íamos, íais, ían. For example: hablaría, hablarías, hablaría, hablaríamos, hablaríais, hablarían. Note that the exceptions to this rule are identical to those recorded for the future tense.
In its simplest form, the conditional may be referred to as a future in the past.
he will do it.” Dice que lo hará.
“Has he done it yet?” ¿Ya lo ha hecho?
“Not yet, but he said he would do it.” Todavía no, pero dijo que lo haría.
... he would do it ... and ... lo haría ... are examples of verbs used in the conditional tense.
Other uses of the conditional include clauses that present a condition or a reservation.
"I would do
it, but ..." Lo haría, pero ...
"I would do it, however ..." Lo haría, sin embargo...
"I would do it , if ...." Lo haría, si ...
Note: we will work further on the conditional when we reach the imperfect subjunctive and subordinate "if" clauses!
Further reading on the use of the conditional tense can be found in your text book.