In Esperanto, the word ankaŭ generally goes before the word it modifies.

Notice the difference in these sentences, in which I have bolded some of the words to demonstrate usage and meaning:

Ŝi havas hundon. Ankaŭ mi havas hundon.
(She has a dog. I have a dog as well.)

Mi amas hundojn. Mi ankaŭ havas hundon.
(I love dogs. I also have a dog.)

Mi havas katon. Mi havas ankaŭ hundon.
(I have a cat. In addition, I have a dog.)

Ankaŭ is not used in Esperanto as a transition word at the beginning of a sentence. Where English speakers tend to say Also, I went to the store, then bought some birdseed, an Esperanto sentence begins with Krom tio …, or Cetere …, or Ne nur tio, sed …, etc.

Ankaŭ at the end of a sentence is pretty ambiguous. Again, English speakers love to put also at the end. But Esperanto speakers expect something to follow ankaŭ. If you’re a new Esperanto learner, I’d encourage you to not put ankaŭ at the end of a sentence.