Learn French: Je suis ici.

Suis is the specific form of the verb être (to be) that matches je (I). Just like in English you say 'I am' rather than 'I is', in French you must always pair je with suis.

Do I pronounce the 's' at the end of suis?

Normally, the 's' at the end of suis is silent. However, because the next word (ici) starts with a vowel, French speakers often connect them. This is called a liaison. You will often hear the 's' pronounced like a 'z', making the phrase sound like 'je sui-z-ici'.

Does je become j' in this sentence?

No, you only drop the 'e' in je and use an apostrophe when the very next word starts with a vowel or a silent 'h'. Since suis starts with a consonant, je stays exactly as it is.

Do I ever capitalize je like I capitalize 'I' in English?

Only when it is the first word of the sentence, like it is here! Unlike 'I' in English, je is written in lowercase when it appears in the middle of a sentence.