In English sentences, when to use be and when to use am is are

In English sentences, when to use be and when to use am is are

Modal verbs such as will can must shall are followed by the original form of the verb
If the subject is directly followed by be, the original be will not be used, but am is are
First person singular followed by am
Third person singular followed by is
The first, second and third person plural followed by are am is a predicate verb. Why use am? Because am can only be used with I. is can be used with the third person singular such as he / she / it. Are is the plural form of is
I am just
I am making... (making is the present participle of make
These are simple tense problems