It is difficult to determine exactly how many proposals you should submit on Upwork to secure your first job as it can vary depending on various factors such as the competitiveness of the job market, the quality of your proposal, and the demand for your specific skills. However, it is recommended to submit as many proposals as possible in order to increase your chances of being noticed by a client. It is also important to ensure that your proposals are well-crafted and tailored to the specific job posting in order to stand out among the crowd. Additionally, being one of the first freelancers to submit a proposal can also increase your chances of getting noticed by a client.