How did the belief of manifest destiny and the issue of oregon lead to the annexation of texas

Manifest destiny made it to where the united states and americans were trying to expand everywhere, this meant that Americans were also going into other countries land (especially Mexico's) A large group of farmers lead by John Austin made an agreement with Mexico to where they would bring mexicans amd farm Texas. They did not fully comply to all the rules in the agreement.  Because the United States had land on the borders of Texas with a strong army and americans already in Texas they basically said this is our land amd started a war ending in the anexation of Texas.