How do you form the present tense for -ar verbs in Spanish?

In Spanish we change the endings of verbs to show who is doing the action. Each verb has a stem and for regular verbs this never changes. To conjugate (form) a verb in the present tense we take the infinitive form like "hablar", which means "to talk". Then we remove the "-ar" ending to leave us with the stem "habl-". We can then add the present tense ending for the person doing the action. If I wanted to say "I talk" we would add an "-o" to the end which would form "Hablo = I talk". In Spanish there are three forms of infinitives: ending in "-ar", "-er" or "ir". Just looking at "-ar" endings like in "hablar" this is what we do. The "-ar" is removed and replaced with: "-o" for I, "-as" for you singular, "-a" for he/she/it, "-amos" for we, "-áis" for you plural and "-an" for they. This would form "hablo, hablas, habla, hablamos, habláis & hablan" = "I talk, you (singular) talk, he/she/it talks, we talk, you (plural) talk & they talk".