Conjugating is not something we normally associate with English verbs. It means giving the different forms of a verb as they vary according to number, person, tense, etc.
It is useful with, for example, Latin, in which the present tense can be ‘conjugated’: amo, amas, amat, amamus, amatis, amant.
The equivalent in English would be: I love, you (singular) love, he/she/it loves, we love, you (plural), love, they love.
There are six different verb endings in Latin, and they need to be learnt somehow. Chanting out the six forms in succession is one way of learning them, and this way is what was commonly meant by ‘conjugating’.
It is far simpler in English to know that the third person singular form of all verbs (with a very small number of exceptions) adds –(e)s.
It may be (and I am guessing here) that your books take ‘conjugating’ to mean learning (perhaps by reciting) the principal parts of irregular verbs. These are: 1. the bare infinitive (also known as the base or first form; 2. the past tense form (also known as the –ed or second form); 3. the past participle (also known as the –en or third form). From these all other verb forms and tenses can be constructed. Examples are:
Go* – went – gone**
Come – came – come
Teach – taught – taught.
Cut – cut – cut.
*From the form go, we can construct goes and going.
**From this we can construct perfect tenses and passive forms.
Student or Learner