At some point in intermediate level, you should learn a list of common verbs that are followed by a second verb in the form of to-infinitive e.g. want, need, agree. Apart from these verbs, the rule is that most other verbs should be followed by a second verb in the -ing form.
In Romance languages, this feature of the language is simpler because you only use the infinitive form of the verb as the form of the second verb.
There are several units in "English Grammar in Use" (Murphy, Cambridge) on this topic.