Desperately need Advice

Need help: I am a newcomer in the world of summer internships(I was in a target school during my Undergrad and so never had to worry about placements much because usually companies recruited right out of campuses), but I am gearing up to apply for summer 2024 internships(no specific preference on the exact divisions yet) in the EMEA and APAC regions, but I am somewhat confused regarding the research, networking necessary and the overall process. For example I am applying for Global Transaction Services Summer Analyst Team at Bank of America, how do I prepare my applications for it, other than the CV and motivations. How deep should i get into research and networking and how to go about it.(I do send out Linkedin connection invites to people working already at the bank, but while i get connection acceptance, there is no follow-up for my messages). Please help me out as I am quite confused with the process.
Also, I have just enrolled into Masters in the EMEA region, so my classes are yet to start, but I have to apply for the internship positions and so I have been attending virtual events on companies as well.
Thanks!