That is a VERY ambitious project for a newbie, maybe too ambitious. Here is my advice.
You start with closing Access, and not opening it for a while. During this time, you think about the requirements for your app: what data goes in, and what data needs to come out. What processing needs to happen. Document this, using text, and maybe some flow diagrams (PowerPoint, or hand-sketched).
At the same time, you read up on the rules of proper database design, such as Normalization. There is plenty of information online. At the end of that you should have a list of about a dozen quality markers of good database design.
Next you crack open the new Northwind 2 template databases. Read the documentation. Understand why things are done this way, learn some best practices, and get some free code you may be able to use in your app.
Next you design the database. No queries, no forms, just the correct database design for your app. Maybe a few sample records for future testing.
Then post that database here for us to provide feedback. Only after the database design is rock solid will you design queries and forms and reports that live on top of it.