Chapter 104 in Tehillim is Barchi Nafshi which we say every Rosh Chodesh at the end of davening. In this chapter of Tehillim, we thank G-d for making the world inhabitable. The Psalmist looks at the different facets of the world and shows us G-d's kindness. Chapter 105 in Tehillim is Hodu L'Hashem kiru Vishmo. We say the first part of this chapter of Tehillim in Pesukay D'Zimra every morning. This chapter of Tehillim was originally said when Dovid brought the Aron to Jerusalem. The theme of this chapter is that we have to thank G-d for everything He has done for us. Therefor, Dovid looks back at what happened to the Forefathers and the Jewish People when they left Egypt.